Aubrey St. Angelo, left, and Rodie Sanchez are the stars of “Killing Fields” on the Discovery Channel. (Courtesy of the Discovery Channel)Derrick Todd Lee, an infamous Louisiana serial killer on death row for murdering two women, became a potential suspect in the investigation of a 1997 murder after The Discovery Channel documentary, “Killing Fields,” reignited the cold case.

But in a strange twist, Lee died this week at a local hospital, according to the Louisiana Department of Corrections. He was 47 years old.

Lee had been transported to the hospital from Angola State Prison, where he was awaiting execution, last Saturday, due to a medical emergency. He was pronounced dead on Thursday at 9 a.m., confirmed Pam Laborde, spokeswoman for the Louisiana DOC.

Lee was the focus of much of the first episode of “Killing Fields,” and appeared to be the main suspect. The timing was strange, said a producer of the show.

“Derrick Todd Lee had been sitting on death row for a different murder conviction,” said Joseph Schneier, Discovery executive producer for “Killing Fields.”

“In the first episode, Derrick Todd Lee was one of the key suspects. You can never anticipate twists like this especially in an active investigation.”

Mugshot circa 2003. (Wikipedia)“Killing Fields” is touted as “an active homicide investigation shot in real-time.” It's directed by the Oscar-winning filmmaker Barry Levinson, and is produced by Tom Fontana, who won Emmies for the shows "Oz" and "Homicide: Life on the Street."

The show brings the detective, who investigated the case, Rodie Sanchez, back from retirement, and pairs him with a young colleague named Aubrey St. Angelo. Together they retrace the trail leading from the 1997 killing of Eugenie Boisfontaine, a 34-year-old woman, outside Baton Rouge, La.

Lee, who had been on death row since 2004, quickly became a person of interest in the revived Boisfontaine investigation.

The 47-year-old inmate was convicted of murdering two women in 2002, and was a suspect in five other deaths in the Baton Rouge area. One of Lee’s confirmed victims lived just three houses down from Boisfontaine, and another lived close by in the area.

READ MORE: Discovery Channel True-Crime Show Follows Hunt Through ‘Killing Fields’

During the first episode, the two detectives even meet with a man who says that Lee personally visited Boisfontaine’s house, and that the killer regularly fished in the area where the woman’s body was dumped.

That first episode ends with the DNA testing of the stains on Boisfontaine’s panties ruling out Lee as a genetic contributor.