And in July 2007 just three months after MacNeill's wife was found dead in her bathtub Vicki Willis witnessed Martin MacNeill get down on one knee and propose to her daughter, Gypsy Jyll Willis.
"They were both very happy," Vicki Willis testified. "He made a speech about his love for her and made a very public show of dropping to one knee and asking her to marry him."
Martin MacNeill, 57, is accused of giving his 50-year-old wife, Michele MacNeill, a fatal combination of prescription drugs after she came home to recover from cosmetic surgery in April 2007. Prosecutors allege the former doctor devised the deadly plan as a way to get rid of his wife to continue his relationship with Gypsy Willis, with whom he started an affair with a year and a half before his wife's death.
Vicki Willis testified on Tuesday that Martin MacNeill once told her he never loved his wife of nearly 30 years, with whom he raised eight children.
"He said, 'Well, I did love her as a sister, but I did not love her the way I love Gypsy,'" Vicki Willis testified.
Gypsy Willis, 37, testified on Tuesday that the day after Michele MacNeill died, she sent several photo text messages to Martin MacNeill, including one of her partially nude back and buttocks.
"There is one picture that is a little bit suggestive," Willis acknowledged.
Willis said Martin MacNeill gave her a 4.5-carat diamond engagement ring, worth about $7,000. Though the couple were never officially married, she said they presented themselves as husband and wife, and she assumed the identity of "Jillian MacNeill."
However, their marriage never happened, perhaps because they both ended up serving time in federal prison on fraud convictions in 2009. In August 2007, the couple had applied for a military identification card for Gypsy Willis, she testified Tuesday. In that application, the couple represented their marriage date as April 14, 2007 the same day as Michele MacNeill's funeral.
At that funeral, Michele MacNeill's friends and family members observed Martin MacNeill acting like anything but a grieving husband.
"He was smiling, joking around," testified Linda Cluff, Michele MacNeill's younger sister. "He was joking, saying that he was going to have to get used to living the life of a bachelor and hanging out with his buddies and golfing."
Michele MacNeill's friend, Loreen Thompson, testified that Martin MacNeill's speech at the woman's funeral seemed odd to her.
"It was very different," Thompson testified. "I just remember his first comment that he made was something to the effect of, he stood there looking at his wife in a pine box. The rest of the talk he gave that day was more about his life and the hard life he's had."
Lani Swallow, Michele MacNeill's friend, testified that she approached Martin MacNeill on the day of the funeral held three days after the woman's death and said she was out of work and could nanny the younger MacNeill children to help out. But Martin MacNeill refused.
"He said that he had already hired a nanny," Swallow testified. "That it was a nurse that he worked with."
Gypsy Willis would move into the MacNeill home eight days later as the "nanny." Though she insisted that she cared for the four young children, Gypsy Willis testified Tuesday that her sexual relationship with Martin MacNeill also continued.
"When the adult children were home, I would defer to them and go back to studying my nursing," she testified. "I did actually help with the children."
Deputy Utah County Attorney Sam Pead ended his line of questioning with Gypsy Willis on Tuesday by asking, "Are you telling us you don't know any more about Michele's death?"
"That is correct," the woman replied.
Michele MacNeill was found unconscious in her bathtub on April 11, 2007, by her 6-year-old daughter, Ada MacNeill. Ada's interview with an investigator at the Children's Justice Center conducted in September 2008 was played Tuesday for the jury.
The video shows the soft-spoken girl, with flowers tied to her braided pigtails, playing with toys as the investigator prods her about what happened to her mother.
Eventually, she tells the woman that she found her mother lying in the tub, fully-clothed in pants and a blue jacket. The water in the tub was brown, the girl said.
Ada said her father sent her to the neighbor's house to get help.
"He was screaming, quick, help," Ada said. "Go next door and get somebody."
Eventually, Michele MacNeill was pulled from the bathtub by a neighbor and Martin MacNeill. The two attempted CPR before medical crews arrived.
Those medical crews also attempted to perform CPR and other life-saving efforts before Michele MacNeill was taken to the hospital, where she was pronounced dead.
Though Ada told the CJC investigator that she missed her mother, she refused to even describe her father, whom she hadn't seen since she moved into her older sister's Nevada homea year prior to the 2008 interview.
"Do you miss your dad?" the investigator asked the child.
"I don't want to talk about it," the girl whispered.
The state medical examiner has never ruled Michele MacNeill's death a homicide. After an autopsy in 2007, her manner of death was ruled "natural," the result of "chronic hypertension and myocarditis, which are capable of causing acute unexpected arrhythmia and sudden death.
But investigations say Martin MacNeill called the medical examiner multiple times and gave misleading information. In 2010, in a new investigative report, Chief Medical Examiner Todd Grey changed the cause of death to the combined effects of heart disease and drug toxicity. The manner of death was changed to "undetermined."
Four drugs were found in Michele MacNeill's blood after her death: oxycodone, promethazine, diazepam and zolpidem, which is also known as Ambien.
The prosecutors' theory that Martin MacNeill drugged his wife and may have drowned the woman was challenged Tuesday after it was discovered that the drug promethazine used as a sedative or sleep aid was incorrectly analyzed by experts working the case, and that the level of promethazine found in Michele MacNeill's system was lower than initially thought.
Deputy Utah County Attorney Chad Grunander told members of the media Tuesday that it is unclear whether the lower drug level will affect the expert's testimony at trial.
"We're going to soldier on," Grunander said. "It's one part of a big case."
Defense attorney Randy Spencer said outside of court Tuesday that they believe this only helps them to prove that Michele MacNeill wasn't overmedicated. He said he feels "optimistic" about the trial so far.
"All in all, there has been no evidence of homicide shown," Spencer said.
Martin MacNeill is charged with first-degree felony murder and second-degree felony obstruction of justice. Three of his adult daughters Alexis Somers, Vanessa MacNeill and Sabrina MacNeill are expected to testify Wednesday.
The trial has been scheduled to last five weeks.