In 2012, George Cortez was convicted of murdering Nasif Murray on a street in North Philadelphia and sentenced to life without parole. Then, in 2016, after further investigation pointed to a different shooter, he was exonerated.

Cortez was shot dead at age 36, just two months after being released from prison. Now, Philadelphia’s justice agencies — including police, court, prosecutors, and public defenders — are hoping to learn from his case.

What went wrong and how to fix it is the subject of a new report by the Philadelphia Event Review Team, a collaboration between those agencies and the University of Pennsylvania’s Quattrone Center for the Fair Administration of Justice.

The Quattrone Center, part of Penn’s law school, is seeking to implement such reviews in jurisdictions across the country, and has received a $1.6 million grant, as part of a joint partnership from the National Institute of Justice and Bureau of Justice Assistance, to take the “Sentinel Event Review” model to between 12 and 20 more cities. Baltimore, Chicago, and Austin, Texas, have already signed on. The idea is to bring to criminal justice the approach long practiced in medicine, where post-mortem reviews examine where errors were introduced and how such failures can be prevented going forward.

“With the help of the Quattrone Center, all stakeholders are able to convene in order to provide better outcomes and the common goal of true justice for all persons," Police Comissioner Richard Ross said in a statement.

The initiative launched in 2015 with a pilot review of the 2000 West Philadelphia mass shooting known as the “Lex Street Massacre” — for which the wrong suspects were held for 18 months before police identified four other men as the perpetrators. In that review, investigators noted that false confessions were a key cause of error, and suggested several changes to interrogation practices.

In the Cortez case, major recommendations include more thorough police record-keeping, greater caution around eyewitness identifications, and court practices that keep pace with evolving technology.

In both cases, investigators urged the adoption of an open-file discovery protocol that would ensure defendants’ legally protected access to potential exculpatory evidence.

First Assistant District Attorney Carolyn Temin said the office has been working toward that protocol. “We have more transparency now with our information than there’s ever been,” she said, though she added that legal issues prevent the office from sharing some evidence.

Cortez was first identified during the police investigation by a surviving victim of the shooting, who mentioned him by a nickname and confirmed his identity after police showed her his photograph by itself, not as part of a photo array.

“It all started with some basic eyewitness issues," said Ross Miller, assistant director of the Quattrone Center. "The eyewitness believed they knew the perpetrator, but there wasn’t any opportunity to test the information that was gathered.”

A second witness named Cortez’s brother, Owen, as the shooter, and a few weeks later called 911 to report that Owen Cortez had been spotted in a neighborhood Chinese takeout.

But police records offer little to document whether police pursued that alternate lead, or what they may have learned. And information about that competing identification was never provided to George Cortez’s lawyer.

At trial, George Cortez’s wife testified that he was with her the entire night, at a birthday party for her son. She even had a video Cortez had taken with her phone. In the interest of moving the trial along, the judge ordered the defense lawyer to hand the phone over to prosecutors so they could upload the video to be shown on the court’s system — but the District Attorney’s Office undertook a broader review of the phone and then claimed, wrongly it would turn out, that information on it had been falsified. The defense never sought a delay in order to get its own expert to challenge that assessment.

All parties wanted to avoid unnecessary delays, the report notes. “Ironically, their emphasis on efficiency, speed, and finality unintentionally led to discretionary choices that made accurate judgments of guilt or innocence more difficult and resulted in countless additional hours of court time during the appellate phase of the case."

When it came time for post-conviction appeals, the phone the district attorney had called into question was nowhere to be found.

Many of the recommended changes in the report have been made. Philadelphia police have already revised practices around how photos are presented to eyewitnesses, and the courts have new rules on the preservation of evidence.

“They are working out the policies in real time over the life of the case,” Miller said. The goal is that all of the changes will ultimately be put in place. “Every participant does so with the agreement that, when they make a recommendation, they’re speaking for their agency.”

After Cortez appealed, his lawyer worked with prosecutors to uncover evidence that pointed away from Cortez and toward his brother, Owen. In 2016, Owen confessed to the crime. He’s serving an 18- to 36-year sentence.

Temin said some of the recommendations suggested by the review of this case, like declining to prosecute if there is only one eyewitness, were not practical. Many rape cases, for instance, hinge on a single witness’ testimony. But she expects the lessons learned to result in a system that’s more fair in the long term.

“The important thing," she said, “is, a mistake was made, and we hope we won’t make it again.”