Police say 17-year-old Zak Hurlburt shot Davis in the head on September 6th at a Manteca House Party.
Davis died on Monday.
Hurlburt was charged with his murder on Thursday.
"He's been charged with murder. He was previously charged with attempted murder because the victim was in a coma. The victim died on Monday, and now the charges were elevated to murder," said San Joaquin County DA Ron Fraits.
The two adults at the party were also arraigned in court on Thursday.
Carlos Calzado and girlfriend Christa McGrath were charged with the criminal storage of a firearm and child abuse or endangerment.
Their bail was set for $200,000 each.
District Attorney Edward McGarvey said they knew a gun was in their home.
"If your kids have a firearm, you need to get rid of it, they didn't do that. They went out and bought alcohol - Old English- for the kids, instead," said McGarvey.
McGrath's attorney asked for recognizance so she could return to work and take care of her children. The judge denied that request.
"You have an 11-year-old and 17-year-old shot. They weren't doing their job," said McGarvey.
Hurlburt will be back in court October 6th. The two adults will be back in court September 26th.