Police spokeswoman Anne Drennan says passengers at a bus loop in New Westminster, B.C., notified officers early Tuesday about a man with a gun sticking out of his jacket.
She says police arrived, arrested the youth as he tried to walk past officers and recovered a loaded air pistol that resembled a Beretta handgun.
Drennan says the youth's 15-year-old girlfriend then told police he bought the gun earlier in the day, and the two spent time drinking alcohol, and shooting at bottles, cans and street signs as they travelled from nearby Coquitlam.
Drennan says a check of the youth's background showed his foster family had reported him missing.
The teens were questioned and released to their foster parents, and Drennan says the incident is still under investigation.