The D.A.'s office tells Action News that Kimbrady Carriker, 40, was ordered by a court-appointed psychiatrist to undergo 60 days of inpatient mental health treatment at Norristown State Hospital.
"Once the court deems this defendant competent to stand trial, the District Attorney's Office fully intends to hold him accountable for the harm and tragedy he has caused. Our thoughts remain with the family, friends, and community that have suffered as a result of Carriker's actions," said D.A.'s office spokesperson Dustin Slaughter.
One of the victims, Joseph Wamah, is believed to have been shot and killed on July 2 - one day before the shooting rampage.
Carriker allegedly opened fire through the front door in the 1600 block of South 56th Street, killing Wamah.
Police were called, but officials acknowledged officers were sent to the 1600 block of North 56th Street, not the 1600 block of South 56th Street - some three miles away. An investigation has been launched into that dispatch error.
Police: Dispatch errors made after first killing by accused Philadelphia mass shooter
Then, on July 3, witness accounts and video of the attack indicated Carriker went to several locations while wearing a ski mask and body armor, carrying an AR-15-style rifle and shooting people and moving cars at random.
The victims killed in the attack include DaJuan Brown, 15; Lashyd Merritt, 21; Dymire Stanton, 29; and Ralph Moralis, 59.
A 13-year-old and 2-year-old also suffered gunshot wounds and two others, including a 2-year-old, suffered wounds from shattered glass, police said.
READ MORE: Mother of 2-year-old shot 3 times in Philadelphia mass shooting speaks to Action News
Mother of 2-year-old shot 3 times in Philadelphia mass shooting speaks to Action News