A man allegedly held captive by his stepmom for 20 years deliberately set fire to their home in Waterbury, Connecticut, last month to escape, police said.

The woman, identified by Waterbury police as 56-year-old Kimberly Sullivan, was arrested Wednesday following an extensive investigation into her stepson’s shocking claims. 

Waterbury police and fire officials responded to reports of an active fire at a residence on Blake Street on the evening of Feb. 17. Police said two occupants were inside the home at the time – Sullivan and her 32-year-old stepson. 

Sullivan was able to evacuate safely. Fire officials assisted her stepson out of the home and placed him in the care of EMS because he had suffered smoke inhalation and exposure to the fire. 

Investigators determined that the stepson had endured “prolonged abuse, starvation, severe neglect and inhumane treatment.” 

He was found in a “severely emaciated condition and had not received medical or dental care during this time” and had been provided with “only minimal amounts of food and water, which led to his extremely malnourished condition.”

This photo provided by the Waterbury Police Department shows Kimberly Sullivan being taken into custody for kidnapping and cruelty for allegedly holding her 32-year-old stepson captive for more than 20 years. (Waterbury Police Department via AP)

A warrant was issued for Sullivan’s arrest on Tuesday and officers took her into custody on Wednesday. She is facing a slew of charges, including first-degree assault, second-degree kidnapping and first-degree unlawful restraint. 

Police responded to reports of an active fire at a residence on Blake Street in Waterbury, Connecticut. (Google Maps)

Sullivan was arraigned in court Wednesday, where bond was set at $300,000. She will be placed in the custody of the Connecticut Department of Corrections, Waterbury police said in a news release. 

“The suffering this victim endured for over 20 years is both heartbreaking and unimaginable. This case required relentless investigative effort, and I commend the dedication of our officers and the Waterbury State’s Attorney’s Office,” Waterbury Police Chief Fernando Spagnolo said. “Their unwavering commitment ensured that justice is served, and the perpetrator is held fully accountable for these horrific crimes.”

Fox News Digital has reached out to Sullivan’s attorney for comment.