In 1991, Michigan man Gregory Green stabbed his wife in the face and chest, killing her and their unborn child. Then, he called 911 and waited for police to come.

After serving about 16 years in prison for murder, Green was released on parole with the support of family and friends, including a pastor who lobbied on his behalf and whose daughter Green would marry.

“Gregory and I were friends before his mishap and he was incarcerated,” Fred Harris, a pastor in Detroit, wrote to the Michigan parole board in August 2005. “He was a member of our church … I feel he has paid for his unfortunate lack of self control and the damage he has caused as much as possible and is sorry.”

“If he was to be released he would be welcomed as a part of our church community and whatever we could do to help him adjust, we would,” Harris wrote again a year later.

Green was released in 2008 and later married Faith Harris. They had two daughters, Koi, 5, and Kaliegh, 4.

Then came a shocking slaughter.

Early in the morning of Sept. 21, 2016, Faith Harris-Green found herself bound with duct tape and zip ties in the basement of their home in Dearborn Heights, Mich., just outside of Detroit. Her foot had been shot and her face slashed with a box cutter, prosecutors say.

Her two teenage children — Gregory Green’s stepchildren — were with her, dead of gunshot wounds. She had watched them die. Her two younger children were dead upstairs, poisoned with carbon monoxide.

The killer was Harris-Green’s husband, the same man whose freedom her father advocated for more than a decade ago.

As Green did when he killed his first wife, he called 911 and waited for police to come, authorities said. He had just shot his family and they were inside the house, he told officers.

Green is back in prison. Last week, he received what amounts to a life sentence. He’ll be 97 by the time he’s eligible for parole, according to the prosecutor’s office.

During the sentencing hearing, Harris-Green, wearing a white turtleneck, spoke to her children’s killer, perhaps for the last time. “You are a con artist. You are a monster. You are a devil in disguise. You are now forever exposed,” she said as she stood behind a podium in a Wayne County courtroom. Her ex-husband, in a dark green jail uniform, sat stoically a few feet away, his back toward her.

No punishment will be enough for her children’s deaths, Harris-Green said. “Not even torture and death would be justice,” she said. “Your justice will come when you burn in Hell for all eternity for murdering four innocent children, all because you’re insecure.”

A spokeswoman for the prosecutor’s office said Harris-Green has asked to not be contacted by the media. She was granted a divorce in December, according to media reports.

What prompted Green to kill his family — and why he immediately confessed to it — is unclear. He had been found mentally competent, the Detroit News reported. Last month, when he pleaded guilty to the charges, Green cried as he described what he’d done.

“Unfortunately, I took the lives of Kaleigh, Koi, Chadney (and) Kara,” he said in court, according to the Detroit News. “I shot my ex-wife. I left my two girls in the car … Kara and Chadney … I shot them.”

The car was filled with carbon monoxide while the two children were inside. Investigators found duct tape on the muffler of the car. A plastic tube was attached to it, according to the prosecutor’s office. The bodies were later moved inside the house.

Green also spoke during his sentencing hearing last week. His brief statement was apologetic, but he gave no explanation of the motive behind the violent deaths. “I feel bad for how this has deeply impacted everyone, and may God help them, help me,” he said in court.

Green was denied parole four times — twice in 2004 and twice in 2006 — before he was released in 2008, said Chris Gautz, a spokesman for the Michigan Department of Corrections. If the parole hadn’t been granted, Green would have been released in 2012, Gautz said.

His prison record provided nearly no trace of violence, no hint that years after he would be released, he would commit crimes more brutal than the first. His history while incarcerated appeared clean, if not perfect. Records show that although he was unable to explain the outburst that brought him to prison, he nevertheless followed the rules and stayed out of trouble.

“Excellent, good block reports, good past work history,” reads his parole eligibility report.

“He is respectful to staff and other prisoners. No minor conducts to report,” reads another.

Green had only one misconduct while incarcerated. He was given a ticket in 2002 for getting involved in a fistfight over a television, Gautz said.

By the time his parole was granted in 2008, Green had completed educational programs in prison, Gautz said. He also had plans for work once he was released.

During a news conference in September, Dearborn Heights Mayor Dan Paletko summed up the sheer lack of explanation for Green’s murderous outrage.

“It’s just difficult to understand the motivation. I just don’t understand what happened in this household,” Paletko told reporters. “I can’t fathom this whole process. I just don’t understand it.”