If police try to arrest somebody they must have arrest warrant to arrest him. There are some grounds where police can arrest a person without warrant. Under section 54 of Cr.P.C. Of Bangladesh 1898 and section 41 of Cr.P.C. Of India 1973 police can arrest without warrant if they found one of those ground below ---
Section 54 : Police may arrest without warrant
Any person having in his possession without lawful excuse, the burden of proving which excuse shall lie on such person, any implement of house braking.“An arrest for procession of implements of house breaking can only be made when the police have received some definite information about it. A arrest cannot be made when there is no definite information and it cannot be justified on the ground that on search such on implement happened to be founded in the procession of the person arrested.”------- Emperor Vs Abdul Halim AIR 1942
Any person who has been proclaimed as an offender either under the code or other of the government."Proper publication of proclamation is necessary to arrest a proclaimed offender. “------AIR 1936 Pat 249., 37 Cr.L.J. 318
Any person in whose possession anything is founded which may reasonably be suspected to be stolen property and who may reasonably be suspected of having committed an offence with reference to such thing." The procession of stolen property must be recent and exclusive.” ----------- 8 WR 28
Md. Shahnewaz Zwaki Advocate The Supreme Court of Bangladesh (High Court Division).