The Serial podcast that triggered public fascination with the murder case of Adnan Syed—the Baltimore teen convicted in the 1999 killing of his ex-girlfriend Hae Min Lee—has been downloaded well over 100 million times. One of those listeners was filmmaker Amy Berg.

“I came to the podcast late. I listened to it in the summer of 2015,” Berg recalls. “And I was approached just a couple months later by Working Title Pictures. They asked me if I wanted to do a film about this case…My interest was piqued.”

The resulting collaboration turned into the four-part docuseries The Case Against Adnan Syed, which debuted on HBO in March. It’s now in contention for Emmy nominations in a variety of categories, including Outstanding Documentary or Nonfiction Series.

“As a filmmaker, I wanted to visualize what was in my mind already about the story,” the director tells Deadline, “and kind of go further with the investigation.”

HBO

The docuseries covers much of the same ground as Serial: the disappearance of Lee, a senior at Woodlawn High School in Baltimore County, in January 1999; the discovery of her body several weeks later, partially buried in a wooded park; the anonymous tip to police casting suspicion on Syed, who had dated Lee for a while, until she broke off the relationship.

Berg built on Serial by hiring private detectives to look into the case.

“I wanted to be able to expedite documents and access to information that isn’t publicly available,” Berg explains. “They were able to use their networks to pull things forward for us. So, that was super and very helpful.”

She also interviewed Syed by phone from prison, where he continues to serve a sentence of life plus 30 years.

“His voice is an important part of this story, and he has stuck with his story for all these years,” Berg asserts. “He’s never tried to point the finger at somebody else, or try to come up with an alternate theory about what he was doing that day [of the killing]. He just said the same thing over and over again.”

HBO

As Berg was working on the series, a court in Baltimore granted Syed a new trial, finding his original lawyer did not provide him with an adequate defense. In March 2018 that decision was upheld by a higher court, which cited the attorney’s failure to seek testimony from Asia McClain, a Woodlawn student who said she saw Syed at a public library at the very time police theorized he was off killing his victim.

Berg interviewed McClain for her series. She also tried to interview the key witness for the prosecution, a friend of Syed’s named Jay Wilds, whose testimony had proven so damaging. Wilds claimed Syed had confessed to the killing and had shown him Lee’s body in the trunk of her car. He also said he had helped Syed bury the remains. But his account lacked consistency.

“[Wilds] told his story over and over again differently,” Berg comments. “The facts kept changing.”

The docuseries also cast doubt on the accuracy of cell phone records that prosecutors used to back up Wilds’ timeline of events.

“After the Serial podcast, what was discovered about the cell phone evidence is that there was a fax cover sheet that was not presented to the expert who testified,” she notes. “And it specifically says that [the location of] incoming calls are not reliable. And all of the markers in this case that sealed the deal for Adnan to be convicted were incoming calls.”

HBO

Berg’s series questions why police did not collect physical evidence from the trunk of Lee’s car and points out that what DNA evidence has been tested does not match Syed.

“There’s a great search for more evidence in this case. There were fingerprints that were taken that didn’t match these guys [Wilds or Syed],” Berg states. “And there was DNA evidence that is still untested that could lead to a closer knowledge of exactly what happened that day, but none of that was really taken into account in the first case.”

For those and other reasons, Berg says she is not prepared to consider Syed guilty.

“Do I think Adnan is innocent? I have not been convinced that he did it,” she maintains. “I’ve not seen any evidence to show that he was actually there and committed the crime. So I have to give him the assumption of innocence until proven the other way.”

Just two days before The Case Against Adnan Syed premiered on HBO—despite all the questions raised about the investigation and trial—the Maryland Court of Appeals reinstated Syed’s conviction, reversing the lower court rulings that had offered him a new trial.

“Devastating is the right word,” Berg says of her reaction to the news. “I think it’s devastating to see our justice system fail again.”

But the director says all hope is not lost for Syed, who just turned 39.

“He always has the path of another submission of evidence to get post-conviction relief. There were some new things that came out of our investigation that I think might be interesting to pursue,” she notes, adding, “This case leaves a mark in so many people’s hearts, so I just hope that there is some resolution at some point.”