"You know, how after you have sex and you're laying there and you feel close and talk a little more open?" testified Anna Osborne Walthall, 48, whose affair with MacNeill lasted about seven months in 2005 after they briefly worked together. "It was like that."
Osborne Walthall, who once ran a laser-hair removal business in Salt Lake City for which MacNeill was an advisor, said MacNeill told her he knew about a substance that could induce an "undetectable" heart attack that would make the incident appear natural.
She also explained their affair began after MacNeill offered to serve as a mediator between Osborne Walthall and her then-husband, with whom she was locked in an acrimonious divorce at the time.
MacNeill, 57, is accused of convincing his wife Michele, 50, to have a facelift, then overmedicated her with post-op drugs and may have drowned her in their Pleasant Grove, Utah, home in April 2007. His motive, they allege, was to start a new life with his other mistress Gypsy Willis, 37.
His wife's manner of death has never been medically ruled a homicide, but instead has been classified as "undetermined" with heart disease and drug toxicity partly to blame.
Other Murders?Osborne Walthall had once told investigators that MacNeill confessed to having murdered his own brother when they were young as well as having mercy killed disabled patients at the last facility where he worked – but those claims were ruled not admissible at trial.
In an attempt to discredit her on Wednesday, MacNeill's defense attorney got Osborne Walthall to admit that she was once diagnosed with dissociative identity disorder, but Osborne Walthall denied that it distorted her grasp of reality.
Testimony in the trial is expected to last until mid-November. MacNeill faces life in prison if convicted of murder.