LOS ANGELES (CBSLA) – A man was killed and a woman was critically wounded in a shooting in Hacienda Heights early Thursday morning.

Just before 1 a.m., Los Angeles County Sheriff's deputies responded to a report of gunshots in the 3300 block of Turnbull Canyon Road to find a man dead at the scene. He was not immediately identified.

A woman was rushed to a hospital in critical condition, a sheriff's spokesperson told CBSLA.

Investigators learned the victims were sitting in a parked car on a secluded section of the road, possibly ingesting nitrous oxide, when another car pulled up behind them, a gunman got out and opened fire on them, the sheriff's department reports.

The suspect vehicle was described as a silver sedan last seen traveling south on Turnbull Canyon Road. The shooter was only described as a Hispanic male.

There was no word on a motive. The sheriff's department is investigating.