LONG BEACH, Calif. >> A 15-year-old boy walking home from school was stabbed to death for his backpack, California authorities said.

Keshawn Brooks was assaulted as the suspect tried to snatch his bag Thursday afternoon outside Stephens Middle School in Long Beach, police said. The suspect ran off.

Brooks, a freshman at nearby Juan Rodriguez Cabrillo High School, was given first aid by witnesses before paramedics arrived. The teen was rushed to a hospital, where he was pronounced dead from serious stab wounds.

After interviewing witnesses, investigators named 18-year-old Giovanny Montelongo as a suspect. He was taken into custody at his Long Beach home on suspicion of murder.

“This was a murder. Down outright. And he did not deserve this,” Brooks’ father, Keeyon Layton, told KCBS-TV. “And to the people who came to his aid, I would like to thank you, very much. It pleases me that he was not alone during his time of death.”

The killing occurred as parents were picking up students at Stephens Middle School, police said. Investigators were asking any witnesses to come forward.

The Long Beach Unified School District was providing grief counselors for students Friday.