Explanation:

Section 149, 150 and 151 of Code of Criminal Procedure – 
149. Police to prevent cognizable offences. Every police officer may interpose for the purpose of preventing, and shall, to the best of his ability, prevent, the commission of any cognizable offence. 
150. Information of design to commit cognizable offences. Every police officer receiving information of a design to commit any cognizable offence shall communicate such information to the police officer to whom he is subordinate, and to any other officer whose duty it is to prevent or take cognizance of the commission of any such offence.
151. Arrest to prevent the commission of cognizable offences. (1) A police officer knowing of a design to commit any cognizable offence may arrest, without orders from a Magistrate and without a warrant, the person so designing, if it appears to such officer that the commission of the offence cannot be otherwise prevented. (2) No person arrested under sub-section (1) shall be detained in custody for a period exceeding twenty-four hours from the time of his arrest unless his further detention is required or authorised under any other provisions of this Code or of any other law for the time being in force.