San Diego

A 19-year-old Thousand Oaks man was arrested Tuesday on suspicion of killing Cyrus Lam, a childhood friend and a San Diego college student who was found shot to death last week, police said.

A San Diego police spokesman said Roderick Michael Mathewson was arrested at his Ventura County home. He was taken to the San Diego County Jail.

Lam, a UC San Diego student, was found Feb. 2 in a canyon near the United States International University campus in San Diego. He had suffered multiple gunshot wounds to the head, torso and arm, the San Diego County coroner’s report said.

Homicide Lt. Phil Jarvis said Tuesday that evidence at the scene led police to Mathewson.

“We believe that the motive is a mutual girlfriend,” Jarvis said. “It (apparently) was an argument between two childhood friends who grew up together . . . over a girlfriend which they shared affection for.”

Friends confirmed that the relationship between the two had been strained recently, police said.