Sheriff’s detectives have arrested a 15-year-old boy on suspicion of fatalling shooting his older brother Wednesday night in Fallbrook, authorities announced Friday.

The boy, whose name was not released because he is a minor, was booked into juvenile detention on a murder charge, sheriff’s homicide Lt. Michael Krugh said in a statement.

He’s suspected of killing his brother, 24-year-old Eduardo Delarosa, Krugh said. The preliminary result of an autopsy performed Friday by the county Medical Examiner’s Office indicated Delarosa died of a gunshot wound to his abdomen.

A 911 caller reported the shooting around 8:25 p.m. Wednesday at a residence on Alturas Road near Sancado Terrace, according to Krugh.

When deputies arrived, they found Delarosa lying in front of a residence with injuries to his torso, Krugh said. Personnel from the North County Fire Protection District took the victim to a hospital, where he later died.