WASHINGTON - In a remarkable reversal, Adnan Syed walked out of prison on Monday for the first time since he was a teenager, having spent 23 years fighting his conviction on charges that he murdered his former high school girlfriend, a case that was chronicled in the first season of the hit podcast "Serial".

Judge Melissa Phinn of Baltimore City Circuit Court vacated the conviction "in the interests of justice and fairness", finding that prosecutors had failed to turn over evidence that could have helped Syed at trial and discovered new evidence that could have affected the outcome of his case.

Prosecutors have 30 days to decide if they will proceed with a new trial or drop the charges against Syed, who was ordered to serve home detention until then. Prosecutors said that an investigation had pointed to two possible "alternative suspects", although those individuals have not been named publicly or charged.

"At this time, we will remove the shackles from Mr Syed," Ms Phinn declared after announcing her decision.

Moments later, Syed walked onto the courthouse steps, smiling as a crowd of supporters shouted and cheered. He gave a small wave and climbed into a waiting SUV, without saying anything to reporters who pressed around him.

Syed, 41, had been serving a life sentence after he was convicted of strangling his high school classmate and onetime girlfriend Lee Hae-min, whose body was found buried in a park in Baltimore in 1999.

Syed, who was 17 at the time, had steadfastly maintained his innocence, and questions about whether he had received a fair trial drew widespread attention when "Serial" debuted in 2014.

The podcast became a pop-culture sensation with its detailed examination over 12 episodes of the case against Syed, including the peculiarities of his lawyer, who agreed to be disbarred amid complaints of wrongdoing in 2001 and died in 2004.

But it was not until September that prosecutors recommended that his conviction be vacated and that he be granted a new trial because, they said that "the state no longer has confidence in the integrity of the conviction".

In a motion filed in Baltimore City Circuit Court on Sept 14, prosecutors said that a nearly yearlong investigation, conducted with Syed's lawyer, had uncovered information pointing to the possible involvement of two "alternative suspects", as well as key evidence that prosecutors might have failed to disclose to Syed's lawyers in violation of their legal duty.

The investigation also identified "significant reliability issues regarding the most critical pieces of evidence" used to convict Syed, including mobile phone tower data.

Prosecutors said in the motion that they were not asserting that Syed was innocent. Ms Marilyn Mosby, the state's attorney for Baltimore City, said on Monday that prosecutors were waiting for a DNA analysis that could help determine whether Syed's case would be dismissed or proceed to another trial.

Ms Becky Feldman, a prosecutor in Ms Mosby's office, said at the hearing that the investigation "acknowledged justice has been denied to Ms Lee and her family by not assuring the correct assailant was brought to justice".

Ms Lee's family expressed concern that prosecutors had not given them adequate notice about the move to vacate the conviction. During the hearing on Monday, Mr Steve Kelly, the family's lawyer, asked Ms Phinn to postpone a decision on the motion.

But Ms Phinn rejected the request, and Ms Lee's brother, Mr Young Lee, then joined the hearing on Zoom after Mr Kelly called him at work.

"This is not a podcast for me," Mr Lee said, voice wavering, when he addressed the court. "This is real life - a never-ending nightmare for 20-plus years."

He said he felt betrayed and blindsided by the motion to vacate, and frustrated with the many turns in the case over the last two decades.

"Whenever I think it's over, and it's ended, it always comes back," Mr Lee said, adding: "It's killing me and killing my mother."

Syed's lawyer Erica Suter indicated that her client was stunned to have walked out of prison after spending more than half his life behind bars.

"He said he can't believe it's real," Ms Suter said at a news conference. "Today is both joyful and incredibly overwhelming."

Ms Mosby moved to vacate Syed's conviction as she faces federal charges that she perjured herself to obtain money from a retirement fund and made false statements on loan applications to buy two vacation homes in Florida. That case is continuing. Her lawyer has called the charges "bogus".

Syed had an on-again, off-again relationship with Ms Lee when they were both students at Woodlawn High School in Baltimore County. Prosecutors had theorised that he killed her after she started dating someone else in December 1998.

Key evidence implicating Syed came from a friend and co-defendant, Jay Wilds, who testified that he had helped Syed bury Ms Lee's body.

Prosecutors also used mobile phone billing records to corroborate Wilds' testimony and to show that Syed had been in the area of the park where Ms Lee, 18, was buried.

A jury convicted Syed in 2000 of first-degree murder, robbery, kidnapping and false imprisonment. An appeals court vacated Syed's conviction in 2018, ruling that he had received ineffective legal counsel, but Maryland's highest court reversed that decision in 2019.

Ms Suter brought the case to Ms Mosby's office last year after Maryland adopted a law that allowed people convicted of crimes as juveniles to request that their sentences be modified after they had served 20 years in prison.

As Ms Mosby's office considered the request, additional evidence emerged requiring prosecutors to conduct a more in-depth investigation, the office said.

Significantly, the investigation identified the two "alternative suspects" who may have been involved together or separately and were "known persons at the time of the investigation" but were never ruled out, prosecutors said.

Both had "motive and/or propensity to commit this crime", they wrote. NYTIMES