WHITTIER — Homicide detectives are seeking a gunman who shot and killed a 17-year-old boy late Thursday in an unincorporated county area west of Whittier.

Authorities withheld the name of the victim Friday pending confirmation that his family had been notified, Los Angeles County Department of Coroner Chief of Operations Craig Harvey said.

The shooting was first reported about 10:15 p.m. in an alley behind the 8300 block Norwalk Boulevard, Los Angeles County sheriff’s officials said in a written statement.

“Upon their arrival, (deputies) discovered the 17-year-old male Hispanic juvenile lying in the alley,” Deputy Benjamin Grubb said. “The victim sustained a single gunshot wound to the upper torso and was pronounced dead at the scene.”

The victim was believed to be in an alley behind a friend’s home when shot, investigators said.

The initial investigation indicated the shooter was male, Latino and wearing gang attire, officials said. He fled the area in a dark gray compact car, possibly a Nissan.

No further information was released Friday.

Anyone with information was asked to call the Sheriff’s Homicide Bureau at 323-890-5500.