A man was stabbed to death while allegedly trying to steal a catalytic converter from a parked car in South El Monte early Friday morning.

The man, believed to be between 45 and 50 years old, was stabbed in the chest a few minutes after 2:30 a.m. and declared dead at the scene in the 11200 block of Thienes Avenue, the Los Angeles County Sheriff’s Department said in a news release.

Investigators believe the unidentified man and two others were trying to steal car parts from a vehicle parked in a driveway when a resident of the home came outside and confronted the alleged thieves.

That resident told deputies that he had been awoken by a commotion and saw the men trying to steal his catalytic converter, leading to one of the thieves being stabbed multiple times.

The resident is “being detained for further questioning,” the release added, though officials said he is not being arrested at this point.

The other two alleged thieves, meanwhile, were last seen fleeing eastbound on Thienes Avenue. Tools were left at the scene, officials said.

Anyone with information is asked to call the LASD Homicide Bureau at 323-890-5500. To provide information anonymously, call Crime Stoppers at 800-222-TIPS (8477 or visit lacrimestoppers.org.

Alexis Lewis contributed to this report.