LOS ANGELES (AP) — A man found with "multiple pounds" of marijuana has been arrested in the shooting deaths of three men in a West Hollywood apartment, the Los Angeles County Sheriff's Department said.

Harold Yong Park, 31, of Los Angeles, was arrested Monday during a traffic stop in Lomita, about 20 miles south of West Hollywood, authorities said.

Investigators believe Park stole the marijuana from the victims, who may have been buying the drug from recognized marijuana collectives, then reselling it, sheriff's Lt. Pat Nelson told The Associated Press (News - Alert) in an e–mail.

Nelson declined to elaborate on how they identified Park as a suspect. Investigators tracked Park's vehicle using a patrol car with an automated license plate recognition system, Nelson said.

Detectives were investigating Park's connection to the victims and the motive for the killings, but they believe robbery was involved, he said.

"Any time a significant amount of drugs and/or money are involved, then the likelihood for robberies and related crime are going to increase," Nelson said.

The three victims, brothers Pirooz and Shahriar Moussazadeh and Bernard Khalili, were killed Thursday night in the apartment where two of them lived. All three victims were members of the Iranian Jewish community and moved to the U.S. as young children.

Neighbors heard shots and the apartment manager found the apartment door open and a body inside.

Park was first booked for possessing marijuana for sale. After detectives interviewed him, he was booked for murder. He is being held without bail.

Veronica Lozano, 20, of La Habra, who was with Park, was also charged with possession for sales of marijuana.