A 16-year-old California student was in critical condition after a man three times his age allegedly struck him in the head with a hammer across the street from the victim's high school on Thursday, police said.
Gregory Richmond, 48, was arrested on suspicion of attempted murder after the attack at about 1:15 p.m. local time near Chino High School, in the Los Angeles-area city of some 80,000 residents, Chino Police Department officials said.
The student was airlifted to an area hospital, and the high school and a neighbouring elementary school for younger students were put on security lockdown.
Additional details such as a possible relationship between the man and the student, the motivation for the attack, and the extent of the 16-year-old's injuries were not immediately available, police said.
The school could not be reached for comment.