Baltimore City Circuit Judge Melissa Phinn said that she was vacating Adnan's conviction “in the interest of justice” and has requested a new trial after years of arguing he was innocent.
WATCH: The Case Against Adnan Syed trailer
Adnan, now 41, will be released on home detention. Under state law, prosecutors now have 30 days to decide whether to drop the charges against Adnan or to retry the case.
The ruling Monday came after Baltimore prosecutors filed last week asking for a new trial. They alleged that newly discovered evidence revealed the possible involvement of other suspects.
Adnan's attorneys filed a response in support, pointing to the revelations in the defense's motion.
"Given the stunning lack of reliable evidence implicating Mr. Syed, coupled with increasing evidence pointing to other suspects, this unjust conviction cannot stand," Assistant Public Defender Erica Suter, Syed's attorney and director of the Innocence Project Clinic, said in a statement at the time.
Adnan pictured in 2016
As the podcast had arguably kick-started a new wave of interest in true crime, Serial was a roaring success, with listeners adamant that the police convicted the wrong man for the murder of 18-year-old Hae Min Lee.
Adnan has always insisted he was innocent.
The initial conviction relied on testimony from Adnan's friend Jay Wilds, who claimed that Adnan, at the age of 19, confessed to killing his girlfriend and asked Jay to help him dig a hole to bury the body in Leakin Park where she was found.
The podcast raised questions about the reliability of Jay's testimony, and the evidence that prosecutors had used in their arguments.
In 2019 HBO also released a documentary, The Case Against Adnan Syed, which explored Hae Min Lee's feath and and Adnan's subsequent conviction.