Two people have been arrested and police are searching for another pair after a teenager was assaulted while trying to buy illicit drugs.

Police said the incident began Saturday night when the 17-year-old West Vancouver, B.C., resident arranged by phone to meet the seller for a purchase.

At the meeting place, the youth was threatened with what appeared to be a pistol, robbed of cash and a cellphone and then beaten by two males, who left in a vehicle.

Investigators believe that two other people were in the vehicle at the time of the offence.

Witnesses helped police locate the vehicle and a 17-year-old male and a 19-year-old female were taken into custody.

Police said the young man is still in custody and faces several charges, while the woman was released on a promise to appear in court.

Investigators are seeking a warrant for a third suspect, who is described as a 22-year-old Bowen Island man.

The alleged victim suffered cuts and bruises after being punched several times.