(a) seize, in any public place or in transit, any narcotic drug or psychotropic substance in respect of which he has reason to believe an offence punishable under Chapter IV has been committed, and, along with such drug or substance, any animal or conveyance or article liable to confiscation under this Act, and any document or other article which he has reason to believe may furnish evidence of the commission of an offence punishable under Chapter IV relating to such drug or substance;

(b) detain and search any person whom he has reason to believe to have committed an offence punishable under Chapter IV, and, if such person has any narcotic drug or psychotropic substance in his possession and such possession appears to him to be unlawful, arrest him and any other person in his company. Explanation.-- For the purposes of this section, the expression" public place" includes any public conveyance, hotel, shop, or other place intended for use by, or accessible to the public.