"That's something that fell through the cracks," Deputy District Attorney Edward McCann said in an interview Thursday.
McCann said his office did not evaluate the report to determine whether it should be disclosed to defense attorneys.
As result, the Public Defender's Office said last week that it would seek new trials for many people Boyer arrested.
The defender's office has represented suspects in hundreds of Boyer's cases since the investigation was completed, court records show. Boyer has been involved in more than 500 criminal cases since 2009.
"That this was kept a secret from defense attorneys is outrageous and raises significant concerns about the legitimacy of any conviction in which Officer Boyer was involved," public defender Bradley Bridge said.
Boyer, 46, did not respond to phone, text, and e-mail messages or to a letter left for him at work.
But he is fighting in a federal lawsuit to defend his reputation.
In a handwritten complaint last year, he charged that police officials damaged his credibility when they suspended him for six days because of the 2008 investigation. He seeks $200,000 in damages and pay for the six days. A civil trial is set for September.
Acting as his own lawyer in a hearing before U.S. District Judge Jan E. DuBois in December, Boyer said city judges had been dismissing his arrests because of the 2008 allegations that he "willfully falsified documents and stuff like that," according to court transcripts.
"The [defense] attorneys tried to impeach me because it just goes to my credibility," Boyer told DuBois.
He did not state whether lawyers had obtained the full investigative report.
The findings of the report were contained in a 2011 labor arbitration case Boyer filed. The police Internal Affairs Division previously had ruled that Boyer was guilty of conduct unbecoming an officer because he "continuously and repeatedly placed inaccurate information on official documents" in drug arrests.
Internal Affairs said that in 63 of his drug arrests, Boyer indicated he performed field tests showing suspects were in possession of narcotics - although the field tests were conducted by other officers or not done at all. It also said he disobeyed rules on the handling of seized narcotics.
Although Boyer did not comment for this article, lawyers for the Fraternal Order of Police argued in the arbitration that he was an extremely aggressive officer, and that many of the errors were a result of a flawed computer system that was later fixed.
Arbitrator Ernest Weiss found that Boyer deliberately broke rules of conduct, but he showed some sympathy for the officer in a July 2011 opinion.
"It appears that Officer Boyer . . . was a victim of his own professional enthusiasm," Weiss wrote. "In the interest of productivity (900 arrests in less than two years) he cut some clerical corners. However, there was no showing that any of his erroneous clerical entries were created for personal gain."
Weiss reduced Boyer's suspension from 20 days to six.
Boyer won praise in 2008 when he gave up his badge number, 1410, in honor of Officer Walter Barclay. Barclay, who had worn that number, was crippled after being shot in 1966. He died 41 years later from complications of his condition.
After his death, Barclay's family was given a plaque with badge 1410. Boyer now wears number 4815.
For years, judges have been raising concerns about Boyer's cases.
Last year, Common Pleas Court Judge Paula Patrick said Boyer apparently did not know the rules for making legal arrests, although he had served 16 years on the force at the time. Boyer had testified that he routinely frisked everyone in every car he stopped.
"Isn't that amazingly illegal?" said Patrick, according to court transcripts. "I mean, really."
In that case, Boyer was explaining his 2011 arrest of Tyrone Hargrove in North Philadelphia. After stopping him and checking his driver's license, Boyer testified, he asked Hargrove to step out of the vehicle.
"He was frisked," Boyer told Patrick. "I do that on every car stop."
Boyer testified that after the frisk, he found a loaded .40-caliber Beretta in Hargrove's car. He booked Hargrove on charges of illegally carrying a firearm because he was a felon, previously convicted for drug dealing.
The gun case never went to trial. All evidence was suppressed because an officer must demonstrate a legal justification for frisking people.
"The case law is clear that they have to have a reasonable suspicion that they are armed and dangerous. . . . He does this all the time, routinely, was his testimony," said the judge.
The District Attorney's Office dropped all charges.
In 2009, Judge Karen Simmons ruled Boyer wasn't credible in his testimony about the arrest of Lewis Butcher, a convicted drug dealer.
Boyer testified that almost immediately after he stopped Butcher in November 2007, Butcher confessed to recently having smoked crack cocaine, a contention Butcher denied.
After hearing Boyer and Butcher testify and reviewing Boyer's arrest paperwork, Simmons suppressed all evidence based on the officer's credibility.
The District Attorney's Office, which withdrew charges against Butcher, has said judges rarely rule that police officers are not credible.
Common Pleas Court President Judge Pamela Pryor Dembe said courts do not notify police when an officer is deemed not credible. That, she said, is not the role of judges.
"Detection and prosecution belong to the executive department, not the judicial branch," she said in an e-mail.
In 1963, the U.S. Supreme Court ruled prosecutors must disclose evidence that would enable defense attorneys to show their clients' innocence or impeach the credibility of government witnesses.
University of Pennsylvania law school professor David Rudovsky reviewed the findings of the 2008 police investigation of Boyer and said the report "contains material that could be used to impeach the testimony of the officer in other prosecutions and therefore must be provided to defense attorneys."
The district attorney, however, did not turn over the report to lawyers defending people Boyer arrested, the Public Defender's Office said.
Deputy District Attorney McCann said he opened a review of what went wrong after questions from The Inquirer about Boyer.
McCann said the police Internal Affairs Division in 2008 sent his office a copy of its investigation of Boyer's alleged falsification of reports.
McCann said prosecutors should have reviewed the investigation to determine whether there was material that should be provided to attorneys defending suspects Boyer arrested. If an officer's credibility is brought into question, the District Attorney's Office is supposed to make a determination of whether the officer can be reliably used as a witness in court, McCann said.
None of that happened.
"We did not have an internal discussion," McCann said.
He said he was still trying to determine what went wrong.
Contact Mark Fazlollah
at 215-854-5831 or email@example.com.