A night of drinks and fun in a hot tub ended in horror with two dead and the survivor saying the "devil was at work".
Marianne Shockley, a 43-year-old professor at the University of Georgia, died alongside homeowner Clark Heindel in May 2019.
Emergency services were called to the scene with claims that the well-respected professor drowned in the hot tub.
Things didn't quite add up though and a medical examiner later ruled she had been strangled.
While officers were on the scene, homeowner Mr Heindel, a 69-year-old former psychologist, took his own life.
He left a three-page suicide note, but did not reveal what happened to Ms Shockley.
The bizarre incident is being chronicled in the documentary The Strange Death of Professor Shockley, which airs later today.
Ms Shockley's boyfriend, Marcus Lillard, 41, was the sole survivor of the night.
He told CBS: "The devil was at work."
Describing the bizarre experience he said: "I mean, everything that he could have possibly done to line this thing up to make it confusing and deceitful and it was all there."
Both Mr Lillard and Mr Heindel were named as suspects.
Mr Lillard was indicted for felony murder and additional charges, but that was after a week-long trial was acquitted.
Mr Lillard has always claimed to not remember quite what happened, having drunk a lot of alcohol and taken ecstasy.
"There is good and there is evil and that night, evil came to play," Lillard said.
"God has spent the rest of the time cleaning up this mess, and … there's still some more."
He had been seeing the professor for around two years before the fateful night.
At the time of the professor's death, Mr Lillard said he had gone for a walk into the nearby woods.
He claimed his partner begged him not to leave saying: "Baby … get back in this water with me right now."
He added: "She had fear in her voice and it was … definitely fear."
But still he went and when he returned, he claimed he could see Marianne slumped down with her chin up to her nose underwater.
When asked why he abandoned her by 48 Hours contributor Jonathan Vigliotti, Mr Lillard said: "Because I'm an idiot."
Authorities said they think the two men waited two hours to call 911.
Mr Lillard said he doesn't think it was normal ecstasy he took that night.
He said: "One thing I know for sure is that was no normal ecstasy … it was super potent … and I believe was made with evil hands."
Explaining his thinking, he said: "Well, it killed two people …"
