A teen was seriously injured when someone opened fire on a West Valley City apartment building Sunday.

The 17-year-old male was inside his living room with his family in an apartment near 1800 West and Lake Park Drive (2565 South) at about 8:30 p.m., when a bullet tore through the wall and struck him in the upper leg, said West Valley City police Lt. Dalan Taylor.

Bullets also pierced the wall of an apartment on a lower floor, but no one was injured, Taylor said.

Witnesses estimated five or six shots were fired, Taylor said. Police haven't interviewed anyone who saw the shooter, but investigators believe the shooter was in a vehicle.

"A drive-by is almost always gang-related," Taylor said. "But we don't see any indication that any of the residents of that building are affiliated with any gangs."

Police were still interviewing witnesses Sunday night.