A convicted killer at the center of a popular podcast that raised questions about his guilt and whether he had a fair trial will seek to call an alibi witness who has never before testified and include her testimony in his request for a new trial, which is pending in an appeals court.

The Maryland Court of Special Appeals issued an order Monday remanding the case of Adnan Syed, whose story was the centerpiece of the "Serial" podcast and who is serving a life sentence for the murder of his former high school girlfriend Hae Min Lee, to a lower court so the testimony of the witness who was never interviewed can be added to the record.

The witness, Asia McClain, said in an affidavit that she was in a library with Syed when Lee was killed.

Syed asked the appeals court for a new trial, arguing his attorney failed to adequately represent him.

Syed, 34, was convicted and sentenced to life in prison in 2000.

Last year, the Serial podcast reopened the case in weekly installments, drawing in millions of listeners. Host Sarah Koenig used the podcast to investigate the case and raised questions about the defense attorney, the late Cristina Gutierrez.

Syed's current attorney, Justin Brown, asked for a new trial based on the fact that Gutierrez never called McClain as a witness and did not seek a plea deal for Syed despite his request that she inquire about the possibility. Additionally, in her affidavit, McClain said she was actively discouraged by prosecutors from attending any post-conviction hearings.

The appeals court's order does not guarantee McClain will be allowed to testify. Instead, it states that Syed may file a request with the Baltimore Circuit Court to reopen proceedings to "supplement the record with relevant documents and even testimony" that the appeals court will later review as it makes a determination about whether Syed deserves a new trial.

"This is another big step in the right direction, and it brings us closer to our ultimate goal of getting a new trial for Adnan Syed," Brown said.

McClain's attorney, Gary Proctor, said "if subpoenaed by either party, Ms. McClain, as she's always wanted to do, will fulfill her obligation to testify truthfully to any question asked of her."