Michele reluctantly agreed to the face-lift. She wanted to wait until the summer, but Alexis said her father insisted she do it sooner. Within a week of the initial consultation, Alexis said the surgery was scheduled.
On April 3, 2007, Michele went under the knife for the face-lift procedure. Alexis, who attended the consultations with the surgeon, said her father insisted the surgeon prescribe a combination of powerful painkillers and sedatives -- Lortab, Percocet, Ambien and Valium -- which are almost never administered for this recovery from this kind of procedure.
The surgeon agreed, said Alexis, because "he knew my dad was a physician, so he thought … he knew how to dose different medications.
"It was just bizarre because my mom was very sensitive to medication anyway," she said.
Alexis was prepared to care for her mother at home, but the next evening, she said her father abruptly told her to leave.
"He said, 'Alexis you need to get some rest,'" she recalled. "I said, 'No, I want to stay right here by my mom.' He said, 'I'll take care of her, her medicines tonight.'"
The next day, Alexis said her mother was heavily medicated when she checked in on her.
"She was completely sedated and out of it," Alexis said, adding that her mother mentioned that her dad kept upping her medications.
After Alexis confronted her father about the dosages, MacNeill allowed his daughter to take over her mom's care, and after four days, Michele seemed to be recovering.
With her mother seemingly on the mend, Alexis flew back to Nevada to resume medical school. But within 24 hours, her mother was dead.
At the family home, the day of Michele's death, Alexis told "20/20" that she'd asked her father where the remaining sedatives and painkillers were, but MacNeill's answers kept changing.
"He said, 'I don't know. … The police must've taken [the medications]. I don't know where it is. Check in the garage,'" Alexis recalled him saying.
When nothing turned up, she said she asked her father again, and this time he said they were thrown out. His explanation: "It was making him too sad to look at it. To see this medication," Alexis said, "As soon as I heard that, things were just starting to add up. Everything was adding up."
But if events raised eyebrows for Alexis and Rachel, nothing about Michele MacNeill's death seemed to appear suspicious to the Pleasant Grove, Utah, police. They did not treat the house as a crime scene, collect evidence or interview anyone besides Martin MacNeill, who according to the police report, told them he believed Michele "passed out while preparing the tub."
"I thought that, OK, if this is a healthy woman who died that there would be some sort of big police investigation," said Alexis. "Their police report into my mother's death is about 2½ paragraphs."
The medical examiner ruled that Michele MacNeill died from natural causes, stating that hypertension and an existing heart infection called myocarditis had caused Michele's heart to fail. Police closed the case.
In the meantime, Martin MacNeill seemed to move on quickly. He hastily arranged a funeral three days after his wife's death, and two days later, returned to work as medical director of the Utah State Developmental Center.