Updated

A 15-year-old boy was charged as an adult Tuesday with two counts of murder in the strangling of his adoptive parents — a jail psychologist and a clinic physician's assistant whose bodies were found stuffed in the trunk of the family car.

Moses Kamin appeared in Superior Court for an arraignment that was continued to Wednesday, when he's expected to be assigned a lawyer. He did not enter a plea.

The teenager was arrested over the weekend after police performed a welfare check of his Oakland home prompted when co-workers said Robert Kamin didn't show up for work Friday, the Oakland Tribune reported (http://bit.ly/yoGiZ8 ).

The couple couldn't have children of their own, so they wanted to help a child who'd had a rough start in life, the victim's brother Bruce Kamin told the San Francisco Chronicle (http://bit.ly/y6LOgs).

"Bob's strength was dealing with people in jail, who are in terrible situations and very demanding," Bruce Kamin said. "It's too bad that his own son couldn't benefit from that."

Officers found the bodies of Kamin, 54, and Susan Poff, 50, under blankets in the back of a PT Cruiser parked outside their house in the city's Lake Merritt district. Investigators believe the teenager had tried unsuccessfully to set the car ablaze.

Moses Kamin was arrested the next day after police said he gave a confession.

Officer Phong Tran told the Tribune the boy may have been motivated by tension with his parents over his two recent suspensions from school. He may have feared being disciplined for his latest suspension on Wednesday, Tran said.

Moses, who has a black belt in karate, first strangled his mother Thursday after the two got into an argument about the suspension, police said. He then stashed her body and waited for his father to come home from work and attacked him from behind, they said.

Kamin, a psychologist for the San Francisco jail system, and Poff, who treated homeless patients at San Francisco's Housing and Urban Health Clinic, adopted the boy in 2002.