Martin MacNeill, a Utah doctor, is standing trial for first-degree murder in the 2007 death of his wife, and the drama has been playing out in a Provo courtroom.
MacNeill, 57, is accused of convincing his wife Michele, 50, to have a facelift, then overmedicating her with post-op drugs and drowning her in a bathtub.
His motive, officials allege, was to start a new life with mistress Gypsy Willis, 37.
His wife's death has never been medically ruled a homicide, but has been classified as "undetermined" with heart disease and drug toxicity partly to blame.
Not only that, some think he is behind other mysterious deaths.
On the stand, another mistress of MacNeill's, Anna Osborne Walthall, told the court that the doctor once told her a chilling detail when they were intimate.
"You know, how after you have sex and you're laying there and you feel close and talk a little more open?" his former lover said. "It was like that."
In this case, she said MacNeill told her he knew about a substance that could induce an "undetectable" heart attack and make an incident appear natural.
Osborne Walthall, who once ran a laser-hair removal business in Salt Lake City for which MacNeill was an advisor, had an affair with him for seven months.
She told MacNeill confessed to having murdered his own brother when they were young as well as having "mercy killed" disabled patients at a medical facility.
Those claims were ruled not admissible at trial, however.
In an attempt to discredit her, MacNeill's defense attorney got Osborne Walthall to admit that she was once diagnosed with dissociative identity disorder.
Osborne Walthall denied that it distorted her grasp of reality.
Testimony in the explosive, complex trial is expected to last until mid-November, while MacNeill faces life in prison if convicted of murder in the case.