07/05/2011 06:55 pm ET Updated Sep 04, 2011

Gay Student Threatened Days Before He Was Slain, Prosecutors Say

Trial began this afternoon in the case of a California teenager accused of execution-style murdering a gay classmate at a middle school in 2008.

The Los Angeles Times reports that Brandon McInerney, then 14, walked into his eighth-grade classroom, took a .22-caliber handgun out of his backpack and shot 15-year-old Larry King, who was sitting directly in front of him. McInerney then threw the gun on the floor and walked out of the room.

Prosecutors now say that McInerney carefully planned the murder of his classmate. Deputy District Attorney Maeve Fox said in her opening statement today that McInerney and other boys at school bullied King. When King started to wear high heels and earrings to school, he and McInerney clashed even more. McInerney allegedly mentioned he would shoot King -- the day before the actual shooting occurred, LA Times reports.

According to the AP, court documents reveal that King said "I love you" to McInerney while at school the day before the shooting.

This emotionally triggered McInerney, who was "emotionally pushed over the edge [by King's] inappropriate sexual comments," NBC Los Angeles reports. McInerney's attorneys plan to argue a case of voluntary manslaughter.

McInerney is charged with first-degree murder, and prosecutors have added a hate crime allegation, arguing that McInerney was motivated partly by a hatred of gays. Although McInerney was just 14 at the time of the incident, he is being tried as an adult.

He faces a maximum of 53 years to life in prison if convicted, KTLA reports.