OLDSMAR, Fla. (AP) - Authorities say an 18-year-old is charged with first-degree murder in the deaths of his mother and her boyfriend.
    
The Pinellas County Sheriff's Office says Benjamin Bishop told investigators that he shot his mother, Imari Shibata, and her boyfriend, Kelley Allen, early Sunday following a serious of arguments.
    
Detectives say Bishop called 911 after the shootings and surrendered without incident.
    
According to detectives, Bishop shot the victims with a shotgun he asked a friend to buy him so he could protect himself from gang members. Bishop couldn't buy the gun himself because he was on probation for a domestic battery incident involving Shibata.
    
Sheriff's spokeswoman Marianna Pasha says Bishop is on medication for mental health issues.
    
Bishop was held without bond Sunday. Jail records didn't show whether he had an attorney.