PROVO, Utah (AP) — The conviction of a Utah doctor in the murder of his wife was the culmination of a yearslong pursuit of justice for the family of the victim.

The daughters and sisters of Michele MacNeill hounded authorities to investigate Martin MacNeill amid an initial finding that the 2007 death was natural, possibly from heart disease. They attended court hearings and sat in the front row of the courtroom at a 2012 preliminary hearing holding photos of Michele MacNeill. They were in Provo again throughout this three-week trial, listening intently. Several of them testified.

When the verdict was read, they let out a loud yelp before dissolving in tears as the jury delivered its verdict to the tense, packed courtroom.

“We’re just so happy he can’t hurt anyone else,” said Alexis Somers, one of his older daughters and his main protagonist. “We miss our mom; we’ll never see her again. But that courtroom was full of so many people who loved her.”

The jury convicted MacNeill of first-degree murder about 12 hours after getting the case, returning the verdict after 1 a.m. He faces 15 years to life in prison when he is sentenced Jan. 7. He also was found guilty of obstruction of justice, which could add 1-15 years.

MacNeill, 57, showed little emotion when the verdict was read. He hugged his lawyer and said, “It’s OK.” Deputies led him back to Utah County jail.

Randy Spencer, one of his lawyers, said he was disappointed before declining further comment.

The Utah doctor was convicted after prosecutors built a case based largely on circumstantial evidence. He was accused of hounding his 50-year-old wife to get a face-lift, pumping her full of drugs and helping her into a bathtub. Prosecutors contend that MacNeill was “swapping” his wife for a new life with a mistress without having to go through a divorce.

Gypsy Willis’ testimony was the highlight of the three-week trial. MacNeill introduced her as a nanny within weeks of his wife’s death, but his older daughters quickly recognized her as his secret lover. They said her mother had been arguing with her husband over the affair.

The daughters went to work uncovering what they call their father’s secret life. They dogged county officials to open an investigation that local police never conducted. It wasn’t until MacNeill’s release in July 2012 from a federal prison in Texas on charges of fraud that Utah prosecutors moved to file charges of murder and obstruction of justice.

Willis also served a federal sentence for using the identity of one of MacNeill’s adopted daughters to escape a debt-heavy history. That daughter had been sent back to Ukraine, supposedly only for a summer.

For a time, MacNeill’s only family defender was his only son. Damian, a 24-year-old law student, committed suicide in January 2010, according to his sisters, who have said he was haunted by their mother’s death.

The case shocked the Mormon community of Pleasant Grove, 35 miles south of Salt Lake City, and captured national attention because the defendant was a wealthy doctor and a lawyer, a father of eight in a picture-perfect family and former bishop in his local congregation of The Church of Jesus Christ of Latter-day Saints.

Defense lawyers contend Michele MacNeill died of natural causes. They believe she had a heart attack and fell headfirst into the tub and noted the autopsy showed she had an enlarged heart, a narrowing of the heart arteries and liver and kidney deterioration.

“There’s simply no proof” of homicide, Spencer said. “The prosecution has presented to you their cherry-picked portion of the evidence.”

He called the testimony of a handful of prison inmates angling for early release doubtful. The 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.

Their testimony was the only direct evidence of murder, chief prosecutor Chad Grunander said. MacNeill lawyers argued he would never admit murder to strangers in prison.

Grunander said the largely circumstantial case was the most difficult he ever brought to trial and that many prosecutors wouldn’t bother trying, especially with medical examiners unable to produce a finding of homicide.

“It was an almost perfect murder,” Grunander said in his closing argument, asserting MacNeill “pumped her full of drugs” that he knew would be difficult to detect once she was dead.

An early mistress of MacNeill’s testified he once confided he could induce a heart attack in someone that would appear natural.

Family testimony suggested it was MacNeill who insisted his wife, a former local beauty queen in her California hometown, get the cosmetic surgery. Prosecutors said he used it as an excuse to mix painkillers, Valium and sleeping pills for her supposed recovery.

“Make no mistake, the defendant’s fingerprints, if you will, are all over Michele’s death,” Grunander said.

Prosecutors said MacNeill might have gotten away with a perfect murder, but his erratic behavior the day of his wife’s death and shortly afterward was “dripping with motive.”

They reminded jurors about testimony that MacNeill stood in the bathroom yelling what prosecutors called phony grief, “Why did you do this? All because of a stupid surgery,” as paramedics tried to revive his wife.

MacNeill was medical director of the Utah State Development Center, a residential center for people with cognitive disorders, who moonlighted in other medical jobs. He had a law degree but wasn’t known to practice law and has since surrendered his law and medical licenses.

Prosecutors say MacNeill contrived a medical condition in the weeks leading up to his wife’s death, telling many around him he was dying of cancer or multiple sclerosis to absolve him of any motive in the death. He also made use of a cane and could be seen limping at times.

Investigators who subpoenaed MacNeill’s own medical records found he was in good health.