A 15-year-old boy who shot a gay classmate twice in a computer room and then walked away deserves to be tried as an adult, prosecutors in California have said.

In documents to the court they argue that Brandon McInerney should be brought before an adult court because of the “execution” nature of his crime.

His laywers filed an appeal last week against the decision.

Lawrence King, 15, who self-identified as gay and wore feminine clothing, was shot in the head on February 12th 2008 during a lesson, allegedly by McInerney, his classmate at E.O. Green Junior High School in Oxnard, California.

“Brandon McInerney sat behind King in a computer lab class … didn’t do anything for 20 minutes, and then without saying a word fired one shot into the back of King’s head,” according to prosecution documents published in the Ventura County Star.

“As the teen collapsed to the floor, McInerney stood up, looked around at his astonished classmates and delivered a ‘second, coup de grâce’ shot into King’s head.”

Prosecutors said McInerney “dropped the gun, raised his hood and according to witnesses, ‘power walked’ out of the classroom.”

They also submitted evidence that the accused bullied several pupils on a regular basis, including the victim, and had made several threats to shoot Mr King.

The accused, who says he is not guilty and is being held in custody, is also facing trial for committing a hate crime.

As he is being prosecuted as an adult he could be sentenced to 50 years in jail if convicted.

His lawyer, Scott Whippert, has challenged legislation that allows prosecutors to decide to try people as young as 14 as adults.

“Someone like Brandon, who was barely 14 and had no juvenile record, should have gone before a juvenile judge, who would look at certain factors to determine whether he is suitable for rehabilitation,” Mr Wippert said.

“But the District Attorney is saying, ‘I don’t have to explain myself to anyone.’ That’s too much power. We as a community should be able to make sure what they are doing is right.”

The Gang Violence and Juvenile Crime Prevention Act of 1998 was approved by California voters in a ballot measure.

Mr Whippert claims that prosecutors did not investigate McInerney’s school or family life, which violates the defendant’s constitutional right to due process.

In April a coalition of 27 LGBT rights groups called for him to be treated as a juvenile.

Kevin Jennings, Executive Director of GLSEN, the Gay, Lesbian and Straight Education Network, said:

“This incident of senseless violence is truly horrifying, and our hearts go out to the student’s friends, family and the E.O. Green School community.

“As a nation, we’ve had our heads in the sand for far too long. We need to do everything we can to prevent something like this from happening again.”