Allen was not involved in the robbery and was trying to calm the situation down, even offering to pay for the pizza, Williams said.
Ellison shot Allen after a brief argument, Williams said, and the bullet severed Allen's spinal cord, leaving the father of three a paraplegic.
Allen spent the rest of his life in hospitals, fighting medical complications stemming from the shooting. He died in February 2009.
Ellison told police he shot Allen in self-defense when he thought Allen was reaching for a gun. Ellison's service-issued Glock 17 was the only weapon recovered at the scene.
Fortune, who goaded Ellison toward violence in the moments before the shooting, police said, screaming for him to "pop one of these [expletive]," was charged with conspiracy and recklessly endangering another person.
The charges followed a nearly two-year grand jury investigation launched by Williams after his predecessor Lynne M. Abraham declined to the prosecute the controversial case.
Police Commissioner Charles H. Ramsey fired Ellison, a nine-year veteran, and Fortune, a 13-year veteran, after an internal-affairs review in 2010 of Allen's death.
Rosie Rosado, 24, the mother of Allen's three children, said she broke into tears when she got the call Friday morning from the District Attorney's Office.
"I'm grateful to Seth Williams," she said, "for looking at this case as long as he has."
She said she regarded this as "a little taste of justice."
She said she has seen Allen's face every day in the faces of their three small children, the youngest of whom she was carrying when Allen was killed.
"I hope one day I can tell them that their daddy got the justice he deserves," Rosado said, "and give my kids some type of closure."
Williams, who took office in 2010 promising to take a fresh look at controversial police-shooting investigations like Allen's, said the charges against the former cops delivered a clear message.
"We will prosecute you for your crimes, no matter who you are, no matter what job title you may have," he said during an afternoon news conference.
"This young man was shot over a pizza by someone who was supposed to protect and serve our community," Williams said. "Words cannot adequately describe how tragic that is."
The grand jury met twice a week since August 2010, Williams said, hearing testimony from dozens of Allen's family members and neighbors, police and expert witnesses.
"We took a long time putting every witness we could in front of the grand jury, and in consideration of all of that evidence, this was their determination," said Assistant District Attorney Gail Fairman, who is handling the case.
The sad, senseless chain of events leading to Allen's death began on the night of the shooting, when Ellison's son and Fortune's son, also 14, were robbed by an unarmed 16-year-old named Demetrius Haywood outside of Bruno's Pizza, at 19th Street and Cheltenham Avenue, according to the grand jury report.
The boys told their parents they knew Haywood from middle school.
Instead of dialing 911, Ellison - armed with his service handgun - and Fortune, set out in Ellison's SUV, with Ellison's son and Fortune's teenage daughter, looking for Haywood, whom they eventually spotted near Cheltenham Avenue.
Ellison hopped from the car with his gun drawn. Haywood ran, and Ellison's group chased him in the SUV, careering the wrong way down Renovo.
Ellison again drew his gun, this time encountering Allen who lived on the block, and who was "attempting to calm the situation," according to the grand jury report.
By every witness account, Allen was trying to defuse the situation, Williams said.
"Why do you have the gun out - all of this over a pizza?" Allen reportedly said. "I'll give you money for the pizza."
Fortune was "agitated, screaming, and jumping up and down," calling Ellison names and asking him if he was "going to let them do this to your son."
"She basically punked him into, in many ways, this shooting," Williams said of Fortune.
Ellison, who was considerably taller than Allen, pushed Allen toward his car, then shot him once from behind, Williams said. The two former officers fled the scene, crossing into Cheltenham Township before flagging down a police officer there and returning.
There was some "inconsistent testimony" from witnesses about whether Allen was armed, but the grand jurors, according to the report, "determined that the credible evidence established that Ellison chose to handle the matter himself, rather than calling 911, was the aggressor and pursuer, and remained so throughout the violent confrontation that he and his family brought to Allen's doorstep."
"The shooting of Lawrence Allen by Chauncey Ellison was the result of emotion and passion, not reason," the jurors concluded.
Ellison and Fortune were scheduled to turn themselves into police late Friday afternoon, Williams said.
A bail hearing has yet to be set.
If convicted, Ellison could face up to 67 years in prison, while Fortune could face 22 years.
Charles Auspitz, an attorney representing the Allen family, said the family has also filed a civil lawsuit against the city.
Contact Mike Newall
at 215-854-2759 or firstname.lastname@example.org.