A Cobb County judge directed a verdict of not guilty by reason of insanity Thursday for a man who killed his mother with multiple gunshots.

But District Attorney Vic Reynolds said he disagreed with the decision, which while unlikely could allow the killer to be released from a mental health facility within months.

“I’m disappointed,” Reynolds told The Atlanta Journal-Constitution. “There’s no doubt he did what he was accused of doing. He killed his mother.”

A jury could have found Mario Dorce guilty but insane, Reynolds said. Instead, Judge Robert E. Flournoy granted a directed verdict. Dorce will be committed to a state mental hospital and be re-evaluated after 30 days, when a hearing will be scheduled to determine if he should remain in the treatment facility, Reynolds said. Dorce will continue to be re-evaluated every 12 months until he is deemed able to be released, the DA said.

Mario Dorce shot his mother 15 times with a 9 mm handgun in their east Cobb home on July 30, 2011, according to investigators. At the time, Dorce was 23 and a college student, The Atlanta Journal-Constitution previously reported.

Police were called to the Tritt Springs Trace home, where they found the body of 52-year-old May Carole Whitty. Whitty had been a bus driver for Cobb County schools since 2002, according to a school system spokesman.

The night before Whitty was shot, she believed her son was possessed by the devil, and she called a friend to her home to pray over Dorce, his attorney, Maddox Kilgore, said Thursday.

While being arrested, Dorce was seen singing and dancing in the back of a patrol car, neighbors previously said.

Witnesses testified during the trial about Dorce’s mental illnesses, Kilgore said in an emailed press release.

“During the nine-day trial there was evidence presented that Dorce suffered from a severe form of bipolar disorder and had delusions that that he was becoming an angel, and that the Book of Revelation was actually a prophecy about him,” Kilgore said.

According to a psychologist, Dorce was delusional and believed his mother was the Antichrist, referring to her as 666 during a police interview, Kilgore said.

Dorce had been in jail without bond since his 2011 arrest.