Adnan Syed, whose murder conviction became the subject of the popular long-form podcast “Serial,” has been granted a new trial.

On Thursday, Baltimore Circuit Judge Martin Welch vacated Syed’s murder conviction, writing in his order that Syed’s former attorney rendered “ineffective assistance” by failing to cross-examine a state expert about the reliability of cell tower location evidence.

“This was the biggest hurdle. It’s really hard to get a new trial, and the improbability of all of this — there was a time when this was initially denied,” Syed’s attorney, C. Justin Brown, said at a news conference Thursday.

Syed, now 35, was sentenced to life in prison in the 1999 murder of his former girlfriend and fellow Woodlawn High School classmate, Hae Min Lee. His original lawyer, Cristina Gutierrez, died in 2004.

Cell tower evidence, used by prosecutors during his murder trial to place him near the burial site, was an element that was explored by journalist Sarah Koenig in “Serial.”

At one point, Syed’s new attorneys had filed an appeal “that was analogous to putting the last nail in the coffin,” Brown said. “Sarah Koenig articulated it pretty well in ‘Serial’ when she said this case is just hanging by a string. And it literally was — statistically, it was over, so we have come back from that.”

“We are thrilled that after 17 years Adnan is finally getting the justice he deserves,” Rabia Chaudry, a friend of Syed’s who first brought his case to Koenig’s attention, told The Post in an email. “And I’m also thrilled that the world is witnessing the terrible systemic problems in the criminal justice system.”

Brown said he expects the state to appeal the judge’s decision.

Prosecutors have long maintained that Syed strangled Lee and then buried her body in Baltimore’s Leakin Park in 1999.

More recently, they have argued reopening the case would be “inconsequential theater and not in the interest of justice.”

Lee’s family also said new hearings “reopened wounds few can imagine.”

“It remains hard to see so many run to defend someone who committed a horrible crime, who destroyed our family, who refuses to accept responsibility, when so few are willing to speak up for Hae,” the family said in a February statement released by the attorney general’s office, the Baltimore Sun reported.

Ahead of a post-conviction hearing in which Syed’s attorney asked for a new trial, Maryland Deputy Attorney General Thiru Vignarajah said “the testimony and records that are already in evidence reveal that Syed received a tenacious and dogged defense in 1999 and 2000 by a team of some of Maryland’s best lawyers.”

He added: “To think there was an oops or an oversight back then, let alone a failure of constitutional dimension, is just not consistent with what we are now seeing in the defense’s file.”

Thursday, Vignarajah’s office said “it is the continued desire of the Attorney General to seek justice in the murder of Hae Min Lee,” according to a statement reported by the Baltimore Sun.

“The state’s responsibility remains to pursue justice, and to defend what it believes is a valid conviction,” the statement read.

Earlier this year, Welch reopened Syed’s case to allow lawyers to introduce new evidence relating to just two issues: the reliability of cell phone tower evidence used during the original trial and an alibi witness.

In a 2015 affidavit, Asia McClain said she remembered talking with Syed in the library at the time prosecutors said Syed killed his former girlfriend. McClain said she reached out to Syed about helping with his defense, but his former lawyer never contacted her.

Syed’s lawyers also argued for a new trial because of his counsel’s failure to contact a potential alibi witness. Welch denied that request, and instead vacated Syed’s sentence because of the cell tower issue.

Brown said his team will explore whether they can have Syed, who is currently imprisoned in Western Maryland, released on bail.

They said Thursday that they have been unable to get in contact with Syed to deliver the news. But, said Brown: “I have little doubt that someone has given him the news of what happened today.”

“Think of it as the conviction is erased. It’s gone,” Brown said. “So if the state were to retry him, essentially, we would be starting from scratch. The whole trial could potentially start again.”

Syed’s brother, Yusuf, told the Sun that his family was ecstatic.

“I had a feeling in my heart it was going to happen,” he said, according to the Sun. “We are just very happy. It’s not only a win for us but a win for a lot of people who are stuck in the system, because it opened a lot of people’s eyes about the justice system.”

This story has been updated and corrected. A previous version misidentified the school Syed and Lee attended.

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