SALT LAKE CITY (AP) -- Testimony concluded Thursday in the trial of a Utah doctor charged with killing his wife, with a defense witness disputing prosecutors' assertion that he could have lifted her from a bathtub to save her.
Martin MacNeill was a doctor at a state psychiatric hospital when he found his wife dead in 2007 at the couple's home in Pleasant Grove, 35 miles south of Salt Lake City. He's accused of knocking out Michele MacNeill with drugs after cosmetic surgery, then leaving her to die in the tub.
Martin MacNeill's lawyers argue his wife died of natural causes. They contend she had a heart attack and fell into the tub. A cause of death was never established.
Closing arguments are set for Friday.
Earlier Thursday, Martin MacNeill's mistress testified they pretended to be married and traded love letters while both served prison terms for fraud charges. But she insisted the affair ended years ago and she's seeing a different man.
Prosecutors suggested Gypsy Willis was still in love with Martin MacNeill and was trying to protect him by denying she knew anything about his wife's death.
"Is it fair to say you appear to be minimizing your relationship with the defendant?" prosecutor Sam Pead asked.
"I don't believe so," Willis replied. She said she hadn't spoken to him in 4 ½ years.
Prosecutors tried to show Willis and MacNeill kept up their love affair with letters while serving time in separate federal prisons from 2009 to 2012 on charges involving Willis stealing the identity of one of MacNeill's adopted daughters to escape a debt-heavy history.
Willis said they took out a marriage certificate two months after Michele MacNeill's death but never actually got married.
Martin MacNeill was arrested on the state murder charge shortly after his July 2012 release from a federal prison in Texas.
The most significant defense testimony Thursday came from an ergonomics expert who said it was "highly unlikely" that MacNeill could have lifted his 180-pound wife out of the high-rim tub, especially with him having to bend over to do it.
Prosecutors countered that Martin MacNeill was in good shape and weighed 206 pounds on a 6-foot-2 frame.
But the witness said the forces required to lift Michele MacNeill were three to four times the safe limit for a man of her husband's proportions. He could have damaged his spine trying, said Brett Besser, an industrial hygienist for the Occupational Safety and Health Administration.
"It's not to say it's impossible, but it would be quite a lift," Besser said.
Martin MacNeill told a police dispatcher he was unable to lift his wife from the tub, and it finally took a neighbor's help to accomplish it.
Defense lawyers also called a co-worker of Martin MacNeill's who testified there was nothing unusual about the doctor's demeanor before he left work to discover his wife unresponsive in the tub.
Earlier this week, several men who spent time behind bars with the doctor testified he had acknowledged killing his wife -- or suggested that investigators could never prove he did it.
One inmate, whose identity was withheld by the court, recalled MacNeill saying he had given his wife oxycodone and sleeping pills, helped her into a bathtub and held her head underwater.
Another inmate, Jason Poirier, recalled asking MacNeill how he was able to get away with wearing custom-made shoes in jail.
The doctor replied, "I can get away with a lot of things. I'm getting away with the murder of my wife," Poirier testified.
Poirier took the stand under a limited grant of immunity from possible drug and theft charges. He acknowledged under cross-examination that he avoided a sentence by informing on MacNeill.
A few days later, Poirier said, he asked MacNeill if the remark had been serious.
The doctor replied he was serious, threw up his arms and said, "Look where I'm at," Poirier testified.
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