Section 7(1)(a) in The West Bengal (Prevention Of Violent Activities) Act, 1970
(a)make a report in writing of the fact to a Presidency Magistrate or a Magistrate of the first class having jurisdiction in the place where the said person ordinarily resides; and thereupon the provisions of sections 87, 88 and 89 of the Code of Criminal Procedure, 1898, shall apply in respect of the said person and his property as if the order directing that he be detained, were a warrant issued by the Magistrate;