Presence of house occupant necessary in implementation of search warrant

Dear PAO,

My son was arrested when the police implemented a search warrant in his house and allegedly found prohibited drugs. His wife said they were forced to stay outside the house guarded by a police officer, while the other officers were conducting the search. My son attempted to enter his house, but he was barred by the police since there were already some barangay officials who woud witness the search inside the house. Could you please enlighten us on the procedure to be observed in conducting a search of a house pursuant to a search warrant?