A 15-year-old boy shot in the back of his head by a classmate Tuesday was declared brain dead Wednesday his body remaining maintained on a ventilator for possible organ donation, the medical examiner’ s office said.

The victim, identified as Lawrence King by Oxnard police, was shot Tuesday during a computer lab at E.O. Green Junior High and died at St. John’s Regional Medical Center, Oxnard police spokesman David Keith said, according to the Associated Press.

Police arrested a 14-year-old suspect who fled immediately after the shooting, which occurred around 8:15 a.m. The boy was found a few blocks from the school soon after the shooting, Keith said.

More than 20 other students were in the class at the moment of the scene, but none of them were injured.

Investigators said there seemed to be something bad going on between the two boys.

“It appears to be kind of a personal thing between these two students. Some kind of beef,” Keith said.

The school where the incident happened is in Ventura County, northwest of Los Angeles. It was placed on lockdown for several hours while authorities tried to ensure that everything was safe. About three-quarters of the school’s 1,150 students body showed up for school the second day. Psychologists held counseling sessions to help students go through the unfortunate event.