CNN  — 

The Maryland Attorney General’s office is appealing a new trial granted to Adnan Syed, whose murder conviction was the focus of the first season of the popular “Serial” podcast.

The judge vacated Syed’s conviction and ordered a new trial for Syed, based on claims that the defendant’s trial lawyer failed to cross-examine an expert witness about the reliability of cell tower location evidence.

Prosecutors relied on testimony from a friend, Jay Wilds, who said he helped Syed dig a hole for Lee’s body. To corroborate his account, prosecutors presented cell phone records and expert witness testimony to place Syed at the site where Lee was buried.

Syed was convicted in 2000 and sentenced to life in prison on murder and kidnapping charges.

Baltimore Circuit Court Judge Martin Welch vacated Syed’s conviction and ordered a new trial based on claims that Syed’s trial lawyer failed to cross-examine the expert witness about the reliability of cell tower location evidence.

On Thursday, Syed’s post-conviction lawyer, C. Justin Brown, shared the news on Twitter.

“I will curb my enthusiasm, because there’s still a lot more fighting to go. He’s still not out of jail,” Brown told reporters at a news conference. “We’ve made a lot of progress, but we’re still not there.”

The Peabody Award-winning “Serial” podcast is hosted by journalist Sarah Koenig. The first season focused solely on Syed’s case and became a cultural obsession, netting more than 40 million downloads by the time the season closed out at the end of 2014.

While millions listened along, the program dug into several puzzles surrounding Lee’s death, among them the alibi account of McClain.

Her account did not make it into the defense case, leading Syed to claim ineffective counsel for failing to contact her.

“The (defense) attorney failed to do the simplest thing and just pick up the phone and call this alibi witness and see if she was legitimate,” Syed’s attorney C. Justin Brown told CNN’s Jim Sciutto on “New Day” Friday. “Without ‘Serial’ … I don’t think we would have gotten as far as we did.”

Welch sided with Syed’s claim that his trial lawyer’s failure to contact McClain “fell below the standard of reasonable professional judgment.” But he was not convinced that it prejudiced Syed’s defense “because the crux of the state’s case did not rest on the time of the murder.”

State’s case placed Syed at burial site

The heart of the state’s case relied on placing Syed at the burial site through cell phone records and Wilds’ testimony, Welch wrote.

Together, the two pieces of evidence created the “nexus” between Syed and the killing, Welch wrote.

“Even if trial counsel had contacted McClain to investigate the potential alibi, McClain’s testimony would not have been able to sever this crucial link.”

As for the cell tower evidence, Welch sided with Syed’s claim that his trial lawyer failed to properly cross-examine state witness Abraham Waranowitz on the reliability of cell tower location evidence.

The instructions included the disclaimer, “Outgoing calls only are reliable for location status. Any incoming calls will not be reliable information for location.”

The state’s theory of relying on incoming calls to determine the general location of Syed’s cell phone “was directly contradicted by the disclaimer,” Welch wrote.

“A reasonable attorney would have exposed the misleading nature of the state’s theory by cross-examinining Abraham Waranowitz. The record reflects, however, that trial counsel failed to cross-examine Waranowitz about the disclaimer.”

Brown told reporters that Adnan’s family was speechless on the phone when he shared the news.

When the new trial was granted, the Maryland Office of the Attorney General said that it was committed to defend Syed’s 2000 conviction.

“It is the continued desire of the Attorney General to seek justice in the murder of Hae Min Lee,” it then said in a statement.

CNN’s Laura Ly and Steve Visser contributed to this report.