Criminal law is one of the most fascinating subjects as it touches every aspect of human behavior in their day to day lives. It regulates dealings of a human being with their fellow human beings, State, and political as well as social and economical institutions, in which the State intends to protect them from unwarranted onslaughts, individual or collective, through coercive penal measures. Criminal law is a means of social control. It is a reflection of community values.

What is a Crime?
It is difficult to give a correct and precise definition of crime. In ultimate analysis, crimes arise due to the changing nature of it. A number of social and political forces and factors, individually or cumulatively, play a pivotal role in the formulation of criminal policy of a state.

Constitutional Protection:

Protection In Respect Of Conviction For Offences:

Article 20:
20(1) Ex post facto law:
An ex post facto law is a law which imposes penalties retrospectively, i.e., on acts already done and increases the penalty for such acts. This article imposes limitation on the law making power of the legislature. Generally legislature has power to make both prospective as well as retrospective criminal laws. But this article prohibits the legislature from making retrospective criminal laws.

20(2) Protection against double jeopardy:
This clause says that, ‘no person shall be prosecuted and punished for the same offence more than once.'

20(3) Prohibition against self-incrimination:
This clause says that, ‘no person accused of an offence shall be compelled it be a witness against himself.

Safeguards Against Arbitrary Arrest And Detention:

Article 22:

This article guarantees four rights on the arrested persons:

1. The right to be informed as soon as may be of ground of arrest,
2. The right to consult and to be represented by a lawyer of his own choice,
3. The right to be produced before a Magistrate within 24 hours,
4. The freedom from detention beyond the said period except by the order of the Magistrate.

Indian Penal Code:

Below is the list of heinous crime.

Sec	Offenses	Pre-Requisites	Punishments	Landmark Cases
300	Murder	~ If the act by which the death cause is done with the intention of murder. ~ If it is done with the intention of causing such bodily injury as the offender knows to be likely to cause the death of the person to whom the harm is caused. ~ If it is done with the intention of causing bodily injury to any person, the bodily injury intended to be inflicted is sufficient in the ordinary course of nature to cause death. ~ If the person committing the act knows that it is so imminently dangerous that it must, in all probability, cause death or such bodily injury as is likely to cause death, and commits such act without any excuse for incurring the risk of causing death or such injury as aforesaid.	Section. 302 whoever commits murder shall be punished with death, or imprisonment for life, and shall also be liable to fine.	~ Pattu Rajan and Others v. State of Tamilnadu. ~ Bhupinder Singh v. State of Punjab.
307	Attempt to murder	Whoever does any act with such intention or knowledge, and under such circumstances that, if he by that act caused death, he would be guilty of murder.	Punished with imprisonment of either description for a term which may extend to ten years, and shall also be liable to fine; and if hurt is caused to any person by such act, the offender shall be liable either to imprisonment for life, or to such punishment as is hereinbefore mentioned.	~ Angrej Kaur v. State of Punjab. ~ Case Regina v. Francis Cassidy
Exception to 300	Culpable homicide not amounting to murder	Culpable homicide is not murder if the offender, whilst deprived of the power of self-control by grave and sudden provocation, causes the death of the person who gave the provocation or causes the death of any other person by mistake or accident. ~ That the provocation is not sought or voluntarily provoked by the offender as an excuse for killing or doing harm to any person. ~ That the provocation is not given by anything done in obedience to the law, or by a public servant in the lawful exercise of the powers of such public servant. ~ That the provocation is not given by anything done in the lawful exercise of the right of private defence.	Section 304, Whoever commits culpable homicide not amounting to murder shall be punished with imprisonment for life or imprisonment of either description for a term which may extend to ten years, and shall also be liable to fine, if the act by which the death is caused is done with the intention of causing death, or of causing such bodily injury as is likely to cause death, or with imprisonment of either description for a term which may extend to ten years, or with fine, or with both, if the act is done with the knowledge that it is likely to cause death, but without any intention to cause death, or to cause such bodily injury as is likely to cause death.	~ State of Andra Pradesh v. Rayavarapu Punnayya. ~ Alister Anthony Pareira v. State of Maharastra
359 - 369	Kidnapping & Abduction	~ Whoever conveys any person beyond the limits of India without the consent of that person, or of some person legally authorised to consent on behalf of that person, is said to kidnap that person from India. ~ Whoever by force compels, or by any deceitful means induces, any person to go from an place, it is said to abduct that person.	~ Section 363 says that whoever kidnaps any person from India or lawful guardianship, shall be punishable with imprisonment of either description for a term which may extend to seven years, and shall also be liable to fine. ~ Abduction is only an auxiliary act and is not punishable in itself. Therefore, there is no general punishment for abduction in the Indian Penal Code. But there are some specific punishments for abduction.	~ Geetha and Sanjay Chopra kidnapping case. ~ Pradeep Kumar v. State of Bihar. ~ Bahadur Ali v. King Emperor. ~ Somasundaram v. State.
319 - 338	Hurt and Grievous Hurt	~ Whoever causes bodily pain, disease or infirmity to any person is to cause   hurt. ~ Emasculation, permanent privation of the sight of either eye, permanent privation of the hearing of either of ear, privation of any member or joint, destruction or permanent impairing of the powers of any member or join, permanent disfiguration of the head or face, fracture or dislocation of a bone or tooth, any hurt which endangers life or which causes the sufferer to be during the space of twenty days in severely body pain or unable to follow is ordinary pursuits is to cause grievous hurt.	~ Section. 321 says that the person shall be punished with imprisonment of   either description for a term which may extend to one year, or with fine   which may extend to one thousand rupees, or with both. ~ There are specific punishments for grievous hurt.	~Ranganayakammma v. State of Andra Pradesh. ~Re Marana Goundan case ~Mathai v. State of Kerela. ~Lal Mandi v. State of West Bengal.
304A	Causing death by negligence	The death of any person by doing any rash or negligent act not amounting to culpable homicide.	Punished with imprisonment of either description for a term which may extend to two years, or with fine, or with both.	~ Prabhakaran v. State of Kerela. ~ Somabhai Mangalbhai Dabhi v. State of Gujarat.
391, 396-400, 402	Dacoity and its aggravated forms	When five or more persons conjointly commit or attempt to commit a robbery, and persons present and aiding such commission or attempt, amount to five or more, every person so committing, attempting or aiding, is said to commit dacoity.	~ Section 395 says whoever commits dacoity shall be punishable with imprisonment for life, or with rigorous imprisonment which may extend to ten years, and shall also be liable to fine. ~ There are specific punishments for its aggravated forms.	~ Kusho Mahton v. State of Bihar. ~ Iqbal & Ors v. State of Uttar Pradesh.
390, 393, 394, 401	Robbery and its attempt and preparation	In all robbery there is theft or extortion. When theft it robbery if the offender voluntarily causes or attempts to cause to any person death or hurt or wrongful restraint, or fear of instant death or of instant hurt, or of instant wrongful restraint. When extortion is robbery if the offender voluntarily causes or attempts to cause to any person death or hurt or wrongful restraint, or fear of instant death or of instant hurt, or of instant wrongful restraint or to some other person, and, by so putting in fear, induces the person so put in fear then and there to deliver up the thing extorted.	~ Section 392 says that the offender shall be punished with rigorous imprisonment for a term which may extend to ten years, and shall also be liable to fine; and, if the robbery be committed on the highway between sunset and sunrise, the imprisonment may be extended to fourteen years. ~ There are specific punishments for its aggravated forms.	~ State of Maharashtra v. Joseph Mingel. ~ Ram Baran v. Emperor.
449 - 460	Burglary	Burglary is typically defined as the unlawful entry into almost any structure (not just a home or business) with the intent to commit any crime inside (not just theft/larceny)	Punishment differs with the act and intensity of the crime.	~ United India Insurance Co.Ltd v. M/S.Harchand Rai Chandan Lal. ~ Ram Prakash v. The State of Punjab.
378, 380-382	Theft	Whoever, intending to take dishonestly any movable property out of possession of any person without that person's consent, moves that property in order to such taking, is said to commit theft.	Section. 379 says whoever commits theft shall be punished with imprisonment which may extent to three years, or with fine, or with both.	~ KN Mehra v. State of Rajastan. ~ Ram Ratan v. State of Bihar.
146 -148, 152-156	Riots	Whenever force or violence is used by an unlawful assembly, or by any member thereof, in prosecution of the common object of such assembly, every member of such assembly is guilty of the offence of rioting.	~ Punished with imprisonment for a term which may extend to two years, or with fine, or with both. ~ There specific other punishments	~ Radha Raman Saha v. Emperor. ~ Miku v. State of Uttar Pradesh.
436	Arson	Mischief by fire or any explosive substance, intending to cause, or knowing it to be likely that he will thereby cause, the destruction of any build­ing which is ordinarily used as a place of worship or as a human dwelling or as a place for the custody of property.	Punished with imprisonment for life or the imprisonment may extend to ten year and shall also liable to fine.	~ Malkiat Singh v. State of Punjab. ~ Babulal & Anr v. State.
405-409	Criminal breach of trust	Whoever, being in any manner entrusted with property, or with any dominion over property, dishonestly misappropriates or converts to his own use that property or dishonestly uses or disposes of that property in violation of any direction of law prescribing the mode in which such trust is to be discharged, or of any legal contract, express or implied, which he has made touching the discharge of such trust, or wilfully suffers any other person so to do, commits criminal breach of trust	~ Punished with imprisonment which may extend to seven years, and shall also be liable to fine. ~ There are specific other punishments for their aggravated forms.	~ State of UP v. Babu Ram. ~ Rashmi Kumar v. Mahesh Kumar Bhada.
415-420	Cheating	Whoever, by deceiving any person, fraudulently or dishonestly induces the person so deceived to deliver any property to any person, or to consent that any person shall retain any property, or intentionally induces the person to deceived to do or omit to do anything which he would not do or omit if he were not so deceived, and which act or omission causes or is likely to cause damage or harm to that person in body, mind, reputation or property, is said to cheat.	~ Punished with imprisonment which may extend to one year or fine or both. ~ There specific other punishments in this area.	~  In the High Court of Judicature Madras v. The State. ~ Hari Sao v. State of Bihar.
28	Counterfeiting	A person is said to “counterfeit” who causes one thing to resemble another thing, intending by means of that resemblance to practise deception, or knowing it to be likely that deception will thereby be practiced.	Punishment is for counterfeiting money, making counterfeit seal, counterfeiting device or mark used for authenticating documents. (S.472-477).	~ State Of Kerala vs Mathal Verghese & Ors. ~ Golo Mandla Ram Rao And Ors. vs State Of Jharkhand.
375	Rape	A man said to commit rape if he: Penetrates his penis, to any extent, into the vagina, mouth, urethra or anus of a women or makes her to do so with him or any other person, Inserts, any object or part of the body, not being the penis, into the vagina, urethra or anus of a woman, Manipulates any part of the body of a woman so as to cause penetration into the vagina, urethra, anus or any part of body of woman, Applies his mouth to the vagina, anus of a woman These by against her will, without her consent, with her consent, when her consent has been obtained by putting her or her interested persons to fear of death or hurt, with her consent when the man make her believe that he is his legal husband when not, with her consent when at the time of giving consent by reason of unsoundness of mind or intoxication or administration by him personally or through stupefying or unwholesome substance, with or without her consent when she is under eighteen years of age, when she is unable to communicate consent.	Whoever commits rape shall be punished with rigorous imprisonment which shall not be less than seven years which may extend to imprisonment for life, and shall   also be liable to fine.	~ Nirbhaya Case ~ Unnao Rape Case.
304B	Dowry Death	Where the death of a woman is caused by any burns or bodily injury or occurs otherwise than under normal circumstances within seven years of her marriage and it is shown that soon before her death she was subjected to cruelty or har­assment by her husband or any relative of her husband for, or in connection with, any demand for dowry, such death shall be called dowry death and such husband or relative shall be deemed to have caused her death.	Punishable with imprisonment which may not be less than seven years but which may extend to imprisonment for life	~ Keshab Chandra Pande v. State. ~ Pawan Kumar v. State of Haryana.
498A	Cruelty by husband and relatives	The husband or the relative of the husband of a woman, subject such woman to cruelty like any wilful conduct which is to drive the woman to commit suicide or to cause grave injury or danger to life, limb or health of the woman and harassment of the women by coercing her to meet any unlawful demand for any property or valuable security.	Punishable with imprisonment which may extend to three years and shall also be liable to fine.	~ Joshi v. State of Haryana. ~ Reema Aggarwal v. Anupam.
354	Outraging the modesty of women	A person said to outraging the modesty of women when he assaults or uses criminal force to any woman, intending to outrage or knowing it to be likely that he will thereby outrage her modesty.	Punishable with imprisonment which shall not be less than one year but which may extend to 5 years, and shall also be liable to fine.	~ Ram Das v. State of Bengal. ~ State of Punjab v. Major Singh.
354A	Sexual harassment	A man committing, Physical contact and advances involving unwelcome and explicit sexual overtures. A demand or request for sexual favours. Showing pornography against the will of a woman. Making sexually coloured remarks Shall be guilty of sexual harassment.	Punishable with rigorous imprisonment which may extend to three years or with fine or with both.	~ Vishaka v. State of Rajastan. ~ Vijay Chinee v. State of MP.
366B	Importation of girls	Imports into India from any country outside India or from the State of Jammu and Kashmir any girl under the age of twenty-one years with intent that she may be, or knowing it to be likely that she will be, forced or seduced to illicit intercourse with another person.	Punishable with imprisonment which may extend to ten years and shall also be liable to fine.	~ Kesal Mal v. Emperor. ~ Manik Molla v. Emperor.
375	Child Rape	Child sexual abuse is a sexual crime against children aged less than 13 years. Rape is defined as committing forced sexual intercourse by violence or threat.	Whoever commits rape shall be punished with rigorous imprisonment which shall not be less than seven years which may extend to imprisonment for life, and shall   also be liable to fine.	~ Madhura Rape Case. ~ Ghanashyam Misra vs The State.
312	Miscarriage	Voluntarily causing a woman with child to miscarry if such miscarriage is not be not caused in good faith for the purpose of saving the life of the woman then it's   an offence.	Punishable with imprisonment which may extend to ten years and shall be liable to fine.	~ Jcob George v. State of Kerela. ~ Moidenkutty v. Kunhikoya.
372 & 373	Selling or buying of girls for prostitution	Sells, lets to hire or otherwise disposes and buys, hires or otherwise obtains possession of any person under the age of eighteen years with intent that such person shall at any age be employed or used for the purpose of prostitution or illicit intercourse with any person or for any unlawful and immoral purpose or knowing it to be likely that such person will at any be employed for any such person then it's an offence.	Punishable with offence which may extend to ten years and shall also be liable to fine.	~ Bachu v. State of West Bengal. ~ Dowlat Bee v. Saikh Ali.
317	Exposure and Abandonment	Being father or mother of a child under the age of twelve years or having the care of such child shall expose or leave such child in any place with the intention of wholly abandoning such child then it's an offence.	Punishable with imprisonment which may extend to 7 years or with fine or with both.	~ Jabbar v. State of Uttar Pradesh. ~ Motia V. State of Rajastan.

Other Crimes:

• Gambling Act 1867
  
  • Explosives & Explosives Substance Act 1884 & 1908
  • Forest Act 1927
  • Child Marriage Restraint Act 1929
  • Registration of Foreigners Act 1930
  • Excise Act 1944
  • Essential Commodities Act 1955
  • Protection of Civil Rights Act 1955
     
• Immoral Traffic (prevention) Act 1956
  
  • Copyright Act 1957
  • Arms Act 1959
  • Dowry Prohibition Act 1961
     
• Indian Passport Act 1967
  
  • Antiquities & Arts Act 1972
  • Narcotic Drugs & Psychotropic, Substances Act 1985
  • Indecent Representation of Women(Prohibition) Act 1986
  • Sati Prevention Act 1987
     
• Terrorists & Disruptive Activities Act 1987
  
  • Railways Act 1989

Procedures:

Arrest And Detention:

Arrest and detention is the first phase after which the investigation begins. The offenders must be timely arrested for proper investigation in a serious case. It also makes the criminals fear to commit the crime and it also maintains peace and order among people. Arrest can be done with or without a warrant. The police have the right to arrest both cognizable and non-cognizable offenders. After detention the police would file FIR.

Investigation And Bail:

The main purpose of the investigation is to collect evidence against the criminal. The police or the Magistrate can investigate the person. After filing of FIR the investigation begins. The police investigate with the receipt of information but it is not a condition for the receipt to be present. Investigation means search for the facts and to find whether the crime has been committed or not. It gives them the clarification to file a charge sheet. Next stage is granting or refusal of bail. Bail means temporary release of the accused awaiting trails. Bail would be granted immediately if the crime is less serious. If the crime is serious then the bail would be granted within 48 hours after producing the accused to the court for hearing. If the crime is heinous then bail will not be allowed. The bail can be refuted if the accused did not follow the rules.

Criminal Trail:

Criminal matters are firstly heard in the court i.e., District court>High court>Supreme Court. All the evidences collected during investigation would be submitted before the court. The accused person would be given an opportunity to be heard. If there is no offence committed then the Magistrate would discharge the case. If there is sufficient evidence of the offence then the accused would be sent to jail till final trail. In the trail the prosecution would submit their arguments and the defense can submit their counter arguments.

Duration Of Trail And Sentencing:

The duration of the trail can be too lengthy due to the slow judicial system in India. A complex case trail may even take seven years. There may be frequent adjournments due to absence of lawyers, judges and slow process etc. At the final trail the court may arrest or acquit the accused. If the offender is acquitted then the prosecution will have time to file an appeal. If the person is convicted then the magistrate would fix date for arguments regarding the sentencing of the offender.

Death Penalty:

Death penalty would be given in extreme cases which mean the death of the accused. It takes time than usual to come to a conclusion.

Conclusion:
In India, we have a separate system to follow. We have police officers, courts to decide on the criminal activity. But in today's era people are taking laws in their hands. The advancement in technology is a boon and also a bane. People are updating the crimes in the social media before even the crime is registered. It's injustice to defame someone who has not even proved to be guilty. And even police officers are killing the offenders before they were produced to the magistrate and celebrated by the people. Offenders have the right to be heard. So people should stop taking laws in their hands.

References:

1. Constitutional Law of India by Dr. J. N. Pandey, 54th Edition.
2. Criminal Law by PSA. Pillai, 13th Edition.