The first "Serial" case has not been forgotten -- in fact, it is the inspiration for a forthcoming four-part documentary series.

Coming to HBO this spring, "The Case Against Adnan Syed" continues the work the podcast started. It delves into the 1999 killing of Hae Min Lee and Syed's subsequent murder conviction. A new teaser trailer, released Tuesday, shows that it considers whether Syed was wrongfully convicted and other possible suspects.

Additionally, the preview hints at new evidence and shows snippets of interviews with people close to the case, including Syed himself. "The closer you look, the more you see," the trailer says.

Watch below.

Syed, who was Lee's ex-boyfriend, was arrested in 1999 and found guilty of her murder in 2000. He has been going through the appeals process in the years since, and his case caught international attention after "Serial" debuted in October 2014. The podcast has since devoted another season to the case, and it is also the subject of the podcast "Undisclosed," among other works.

"The Case Against Adnan Syed," which is directed by Amy Berg, premieres on HBO this spring.