 -- His story has been heard by millions since the 2014 launch of investigative podcast, “Serial,” turning listeners into armchair detectives.

Adnan Syed was convicted in the 1999 murder of his high school ex-girlfriend Hae Min Lee, who was found strangled in a Baltimore park. At age 17, Syed was arrested and later sentenced to life in prison. His attempts to appeal were unsuccessful until a Maryland court agreed to give him another chance to present new evidence –- including an alibi witness.

In an exclusive interview with ABC News, Asia McClain explained why she is speaking up 17 years later.

“I was compelled by my children. Keeping that legacy, integrity, and stepping up to tell the truth was very important to me," she said. "I want my kids to know their mom was strong."

McClain testified during Syed’s post-conviction hearing last week, saying she spoke with him at the public library on Jan. 13, 1999 at the very time the state says Syed killed Lee.

“I just happened to be at a specific place at a specific time,” she says.

McClain says she didn’t rehearse for her testimony, and was nervous. She also avoided making any eye contact with Syed during her testimony.

"I didn’t know what the temperament of the prosecutor was going to be," she said. "Just not knowing what to expect was a little fearful."

Though she testified for Syed, she recognizes that the decision as to whether Syed will get a new trial ultimately lies with the judge. The state maintains he belongs behind bars.

“I hope that enough information was presented to the judge for him to be able to make a rational decision," she said. "Whatever that might be, is in his hands.”

And her message to Syed?

“I would just personally apologize that I didn’t come forward in 2010," she said, of when the defense lawyer reached out to her to testify.