Washington (AFP) - Prosecutors in the US city of Baltimore dropped charges on Tuesday against a man who served over two decades in prison for his ex-girlfriend's murder -- a case that drew worldwide attention thanks to the hit podcast "Serial."

Adnan Syed, 41, spent 23 years behind bars after being "wrongfully convicted" of the 1999 murder of Hae Min Lee, Baltimore City state's attorney Marilyn Mosby told reporters.

Baltimore City Circuit Court Judge Melissa Phinn had tossed out Syed's conviction last month at Mosby's request, and ordered his immediate release.

Mosby said Tuesday that recently tested DNA evidence was "exculpatory" for Syed, who has steadfastly maintained his innocence.

"Because of the advances in DNA, we were able to extract DNA from (Lee's) shoes," Mosby said, adding that her murder remains an "open and pending investigation."

The prosecution's initial move to have Syed's conviction quashed was prompted by the discovery of information regarding two alternative suspects and unreliable cell phone data used to convict.

Erica Suter, one of Syed's defense lawyers, said Tuesday that "the results of the DNA testing exclude Adnan and confirm what Adnan and his supporters have always known: Adnan Syed is innocent."

"Today's a day that Adnan Sayed and his loved ones have been waiting for for 23 long years," Suter said. "He is elated. He is joyful. He is still processing this."

Suter said Syed, who could be eligible for financial compensation from the state because of the wrongful conviction, "would like to continue his education."

"I think he has dreams of going to law school," said Suter, who heads the Innocence Project Clinic at the University of Baltimore.

Honor students

Mosby declined to comment on the two alternative suspects Tuesday except to say that the investigation was continuing and her office was determined to provide justice to Lee's family.

"We will continue to utilize every available resource to prosecute whoever is responsible for the death of Hae Min Lee," she said.

After the judge vacated the conviction on September 19, prosecutors had 30 days to either bring new charges against Syed or dismiss the case.

Lee's body was found buried in February 1999 in a shallow grave in the woods of Baltimore, Maryland. The 18-year-old had been strangled.

Sentenced to life in prison in 2000, Syed's multiple legal appeals had been denied, including by the US Supreme Court which declined in 2019 to hear his case.

Syed's saga earned global attention when it was taken up in 2014 by "Serial," a weekly podcast that saw a journalist revisit his conviction and cast doubt on his guilt.

It was also the subject of a four-part documentary on the HBO channel called "The Case Against Adnan Syed."

The "Serial" podcast -- a mix of investigative journalism, first-person narrative and dramatic storytelling -- focused its first season on Syed's story in 12 nail-biting episodes.

Both Syed and Lee were high school honor students and children from immigrant families -- he Pakistani, she South Korean -- who had concealed their relationship from their conservative parents.

Prosecutors said during the trial that Syed was a scorned lover who felt humiliated after Lee broke up with him.