A Wisconsin teenager is facing life in prison for killing a prolific pedophile who she says started having sex with her when she was 16 — and even sold her to other men, according to a report.

Chrystul Kizer, now 19, confessed to killing Randy Volar, who was out on bail while accused of filming himself abusing about a dozen girls, some looking to be as young as 12, the Washington Post said.

Kizer shot Volar, 33, twice in the head last June because he had drugged her and was pinning her to the ground to rape her, she told the paper during more than five hours of interviews from jail.

She allegedly panicked and lit his body on fire to try to hide the evidence at his home in Kenosha, partly inspired by the TV show “Criminal Minds,” according to the report.

Kizer’s case could prove a testing ground for “affirmative defense” laws that allow victims to be acquitted of some crimes if they prove they committed them because they were being trafficked.

However, a judge on Dec. 9 overruled Kizer’s initial bid to apply the law — and prosecutors maintain that the killing was premeditated, the report says, based in part on Facebook posts around the time of the killing. Her lawyer is appealing the ruling, the paper says.

Kizer faces a slew of charges, including arson and first-degree intentional homicide, which carries a mandatory life sentence in Wisconsin. She is being held on $1 million bail, court records show.

When he was killed, Volar had been free without bail despite an investigation into charges including child sexual assault, child enticement and using a computer to facilitate a child sex crime, the report says.

It started last February when a 15-year-old girl claimed he drugged and threatened to kill her, telling cops that Volar had been paying her for sex since she was 14, the Washington Post said, citing police records.

She told officers that her abuser had filmed himself abusing other girls — with officers then finding “hundreds” of child pornography videos of girls who appear to be as young as 12, according to the report.

They included more than 20 “home videos” of Volar with underage girls — including Kizer, who told the Washington Post she did not know she had been filmed. In some, Volar described himself as an “escort trainer,” according to the report.

Officers also found he had $800,000 in assets and had made almost $1.5 million in transfers between November 2017 and May 2018, a pattern of activity his bank associated with human trafficking, the report said.

Kizer said she started having sex for money to pay for snacks and school notebooks, meeting Volar through an ad on Backpage.com.

He then made her have sex with other men in local hotels, sometimes more than once a day, she told the paper, saying she only went along “because he was a grown-up, and I wasn’t. So I listened.”

She said shortly before his death, she had been trying to cut ties because he “had started to talk violent” and threatening to kill her.

The night he died, she says, he gave her drugs that made her feel “weird” and told her she “owed him” when she refused to have sex, she claimed, saying he started ripping off her pants as he pinned her down.

She claimed to not remember grabbing her pistol, just hearing “like a pop. A high pop.”

“I started to panic,” she told the paper.

Kizer said they were “both” victims. “Because of the stuff that he was doing to me. And, that he should have never died,” she said.

Kenosha police declined to comment to the Washington Post.

District Attorney Michael Graveley told the paper that a sex crimes prosecutor had been working to identify all the victims.

“In many and most of the cases, we didn’t know the age,” he said. “So we literally did not know whether we had misdemeanors or felony.”