A 16-year-old Oakland boy pleaded guilty in adult court Monday to two counts of murder for killing his adoptive parents in January.

The surprise plea by Moses Kamin shortly before his trial was to begin calls for him to receive a term of 25 years to life in state prison when he is sentenced by Alameda County Superior Court Judge Jeffrey Horner on Jan. 25.

Kamin pleaded guilty to second-degree murder for the death of his adoptive mother, 50-year-old Susan Poff, and to first-degree murder for the death of 55-year-old Robert Kamin, at the family's home at 284 Athol Ave. in Oakland the night of Jan. 26.

Kamin was 15 at the time but was charged and prosecuted as an adult.

Poff and Robert Kamin both worked for the San Francisco Department of Public Health and adopted Moses Kamin when he was 6.

Robert Kamin had worked with the San Francisco Sheriff's Department since 1994, providing mental health services to inmates, and had also worked as a psychologist at Haight Ashbury Free Clinics-Walden House.

Poff had been employed as a physician's assistant with the San Francisco Department of Public Health's Housing and Urban Health Clinic since 2004.

In a videotaped interview with Oakland police that was played in court at his preliminary hearing, Moses Kamin told investigators he killed his adoptive parents in a fit of anger by using a chokehold he had learned in his years of studying martial arts.

He said he had been suspended from school for smoking marijuana and he didn't want to deal with them being upset at him.

The judge at his preliminary hearing held him for trial, and when Kamin was arraigned a second time, he pleaded not guilty by reason of insanity.

Kamin's attorney, Andrew Steckler, said a psychologist found that the teen suffers from a disorder that affects some adopted children.

Steckler, who couldn't immediately be reached for comment said Kamin has dissociative disorder because of early childhood trauma due to "horrible conditions" he experienced while living with his birth mother, being separated from his siblings and being moved from foster home to foster home.

Kamin's trial had been scheduled to begin soon, and Horner has been holding hearings on a variety of pretrial motions the past two weeks.

If the case had gone to trial, a jury would have decided if Kamin was guilty of the two counts of murder, and if he had been convicted, the same jury would have decided whether he was sane at the time of the killings.

If Kamin had been found to be insane, he would have been sent to a state mental health facility.