A Philadelphia man who served 37 years in prison in a case tainted by perjured testimony was cleared of the murder on Thursday and then sued the US city over his 1984 conviction.

Willie Stokes left prison earlier this month, after a United States federal judge found prosecutors never disclosed that they had charged his chief accuser with perjury after the trial.

The witness has said he was offered sex and drugs at police headquarters to frame Stokes in an unsolved 1980 dice-game slaying.

“I’m not bitter. I’m just excited to move forward,” Stokes, 60, told The Associated Press news agency after the brief morning court hearing, when prosecutors announced they would not seek to retry the case.

More than 100 people have been exonerated and released from prison in recent years in the US state of Pennsylvania, according to Marissa Boyers Bluestine of the University of Pennsylvania law school, the former executive director of the Pennsylvania Innocence Project.

But none served more prison time than Stokes.

More recently, homicides have soared in Philadelphia and other major American cities during the coronavirus pandemic and police are facing new scrutiny, including for past arrests and discrimination, in the wake of social justice protests following the death of George Floyd in 2020.

In New York last month, one of two men wrongly convicted for the 1965 murder of Black civil rights advocate Malcolm X, sued New York state for at least $20m in damages after being exonerated.

In Philadelphia, the trial witness who had identified Stokes as the killer at a preliminary hearing recanted at the murder trial, in what he later called a fit of conscience. Stokes was nonetheless convicted.

Prosecutors then charged the witness, Franklin Lee, with perjury over his pretrial testimony, and Lee went to prison for it. Stokes never knew that until 2015.

“I didn’t believe it,” Stokes said in a telephone interview. “I didn’t believe that they would let something like that happen — that they knew, and they didn’t tell me.”

Stokes said his only child, a daughter who was two when he went to prison, died about 20 years ago. He was not allowed to attend her funeral. He now lives with his mother.

“She [has] got a beautiful three-story house, so I’m not in the way,” Stokes said on Thursday, the joy in his voice evident.

Criminal lawyer Michael Diamondstein, who handled Stokes’s successful federal court appeal, called the actions of police and prosecutors in the case outrageous. “They used perjured evidence to convict him and then charged the perjurer, and never told him. And then Willie was warehoused for 38 years,” Diamondstein said.

In his view, the official misconduct stemmed from “institutional racism, or pure bias”.

In Philadelphia in those days, “the cases needed to be closed,” Diamondstein said. “The inner-city minority were interchangeable, as long as you had someone in the defendant’s chair.”

Philadelphia, the fifth-most populous city in the US, may be liable for damages in Stokes’ imprisonment

Philadelphia District Attorney Larry Krasner has championed about two dozen exoneration cases. A supervisor in his office, Matthew Stiegler, said on Thursday that the office agreed with the federal judge who found that Stokes’s constitutional rights were egregiously violated.

Both detectives who allegedly offered Lee a sex-for-lies deal to help them close the homicide case are now deceased.

“I felt weak and went along with the offer,” Lee told the federal judge in November, recalling his testimony at the May 1984 preliminary hearing.

Meanwhile, Stokes filed a lawsuit on Thursday accusing the city of “outrageous police misconduct”. The lawsuit names the estates of the now-deceased detectives as defendants.

Two surviving prosecutors also named in the suit, now in private practice, did not immediately return messages from AP seeking comment on Thursday. At least one has given a statement saying he does not remember the case, according to court files.

The Philadelphia police department declined to comment on the case. The city did not immediately return a message seeking comment on Thursday.