The suspect, Richard Poplawski, 22, surrendered after a four-hour standoff at his home, the Pittsburgh Post-Gazette reported. He faces three counts of murder and other charges.
The dead officers were identified as Stephen Mayhle and Paul Sciullo III, who had both been with the department for two years, and Eric Kelly, a 14-year veteran. Two other officers were injured.
The day was the deadliest in the Pittsburgh Police Department's history.
Police Chief Nathan Harper said the three officers were gunned down just after 7 a.m. as they arrived at Poplawski's house. The others were shot responding to a call about the first shootings.
During the next four hours, Poplawski, who was reportedly wearing a bullet-proof vest, remained in the house with his mother as officers from the city, the district attorney's office and the state converged on the neighborhood. He made a number of cell phone calls to friends.
Poplawski was hit by several bullets during the standoff.
Eddie Perkovic, a classmate from North Catholic High School, said Poplawski called him about 8:30 a.m.
"Eddie, I'm going to die today. Tell your family and friends I love them. This is probably the end," Perkovic said Poplawski told him.
Perkovic said Poplawski had strong views about the right to bear arms but did not belong to an organized group.