An “evil” Oregon babysitter who sexually abused and tortured three sisters under his care has been sentenced to 270 years in prison after more than a decade of delays, federal prosecutors said.

Andrew Franklin Kowalczyk, 44, was sentenced Monday after the former Portland man was convicted on nine counts of producing child pornography in December by a jury that deliberated for just 20 minutes following his four-day trial, the US Attorney’s Office for the District of Oregon announced Monday.

Kowalczyk, who was originally indicted in February 2008, changed attorneys more than 12 times throughout the case and filed extensive motions to suppress evidence.

He also allegedly tried to have a fellow inmate kill Assistant US Attorney Scott Kerin.

“What this defendant did to these children is simply unexplainable,” Kerin said in court on Monday, according to The Oregonian. “In terms of the sexual exploitation and abuse of children, this defendant is the worst this courthouse has ever seen.”

Kowalczyk plied the girls — an 8-year-old and a set of 2-year-old twins — with toys, food, gifts and motel rooms in Portland, where the girls stayed with him in 2005 as their mother searched for an apartment or sold crack cocaine, the newspaper reports.

Kowalczyk, who had been a family friend, was arrested in 2007 on unrelated charges in Washington state. A subsequent search of his bags revealed roughly 650 images and videos of child porn, according to the newspaper.

Investigators published some of the non-pornographic images that appeared to be homemade in an attempt to track down the victims. The girls’ mother later told investigators that she knew Kowalczyk as a friend of her brother whom she met in 2003 and that he had regular access to her children, federal prosecutors said.

The eldest of the three sisters said in court Monday that she’s still having nightmares and suffers from extreme guilt for not shielding her younger siblings from Kowalczyk’s sadistic abuse, according to The Oregonian.

“Andrew is evil itself,” the woman, now 23, told a judge. “He deserves to rot in prison for the devilish things he’s done to me and my baby sisters.”

The younger girls, meanwhile, do not remember the “horrific things” Kowalczyk did to them, but remain in state custody and struggle with anger toward their mother for leaving them in his care, their attorney said.

Kowalczyk, a 480-pound, wheelchair-bound man, flipped his middle finger at a judge as he was led out of court by four deputies, The Oregonian reports.

“You’re a corrupt piece of [expletive],’” Kowalczyk told the judge.