A pending murder case officially dissolved Tuesday when the Philadelphia District Attorney's Office decided not to appeal a judge's ruling that a former city detective had committed "outrageous" misconduct and irreparably tainted the investigation by developing unusual relationships with several key witnesses.

Darnell Powell had been facing a potential life sentence for fatally shooting 22-year-old Eliezer Mendez in Kensington in 2015, a crime that had been captured on surveillance video and in which another defendant already had pleaded guilty and was expected to implicate Powell.

But the case against Powell, 38, began unraveling last year when his attorney, Robert Gamburg, revealed that homicide detective Philip Nordo had repeatedly deposited money into the prison account of a key witness without disclosing the transactions to others involved in the case.

Last month, Common Pleas Court Judge Diana L. Anhalt took the argument further, ruling that although she was not commenting on Powell's innocence or guilt, the case against him should be tossed because Nordo's misconduct extended to other witnesses.

In one instance, according to a transcript of the hearing, Anhalt said that a written statement allegedly given by a witness to Nordo was "suspect." Anhalt said that the man admitted he had trouble reading the statement, that he appeared "slow intellectually," and that it sounded to her as if Nordo had taken the lead in drafting the statement and simply had gotten the man to agree with it.

In another example, Anhalt said a different witness was recorded telling Nordo on the phone: "I love you." The judge was skeptical that such a sentiment would have been expressed within the typical boundaries of an officer-informant relationship, according to the transcript.

"I would be willing to bet I don't know a whole lot of guys who are telling some white homicide detective up at Eighth and Race, 'I love you, man,' " Anhalt said.

She also said it was "obvious" that there was a "messed-up relationship" between Nordo and witness Rhaheem Friend, whom Nordo regularly paid and spoke to on the phone while Friend was incarcerated.

The result, Anhalt ruled, was a case plagued by "messed-up nonsense," in which nearly every key witness had been tainted by the detective's actions.

"I do think his conduct was so outrageous and so egregious that I don't have faith in the process," Anhalt said before approving Gamburg's motion to dismiss the case.

The District Attorney's Office had until Tuesday to appeal her ruling but declined to do so during a brief hearing. Prosecutors did not explain their decision.

Nordo — who was not at the hearing — was dismissed from the force last summer for what the Police Department called "knowingly and intentionally associating, fraternizing, or socializing" with people connected to criminal conduct. He also was placed on a list of police officers whom prosecutors had sought to keep off the witness stand due to perceived credibility issues.

Last year, a police spokesman said that local and federal investigators were reviewing Nordo's conduct for potential criminal violations. He has not been charged with a crime, and the status of that investigation was not clear Tuesday. Attempts to reach him for comment were not immediately successful. It also was not clear whether Anhalt's decision and criticism of Nordo's behavior would reverberate beyond Powell's case. Before he was fired, Nordo — who spent two decades on the force, nearly half of that time in homicide — was known as a prolific investigator often assigned to challenging investigations.

Gamburg praised Anhalt for ruling that "this entire case was tainted by the conduct that we proved."

Powell remained incarcerated Tuesday on a drug case. His mother, wife, and sister-in-law attended the hearing and said afterward that they felt for the relatives of the victim and were sympathetic to their loss.

They also expressed gratitude that the judge had agreed Powell's homicide prosecution had been plagued by misconduct.

"We're just relieved that it's over," said the sister-in-law, Felicia Collins.