Jack Mook may have a tough exterior, but make no mistake — the Pittsburgh police detective has a heart of gold.

On Sept. 16, the 45-year-old bachelor officially became the adoptive father to 15-year-old Josh and 11-year-old Jessee, Trib Total Media reported. Unfortunately, the two brothers had lived through years of abuse and neglect before falling into the care of Detective Mook.

In the winter of 2012, Mook — a 22-year police department veteran — grew suspicious after Josh and Jessee stopped showing up for training sessions at the Steel City Boxing gym where Mook volunteers, CBS News reported. Mook knew the majority of kids he works with at the gym are underprivileged and living in difficult situations, and he wanted to check in on Josh and Jessee.

“Mostly, kids that come in this gym are street kids,” he told the outlet. “Many of them have been born into poverty.”

After Mook tracked down Josh at school, he learned the harsh reality of the brothers’ circumstances. Josh and Jessee had been living in foster care — in a “dilapidated home [with] roaches [and] rats,” according to KDKA Morning News.

“They have had it as worse as any other kid that’s lived in the city of Pittsburg, living conditions wise,” Mook told CBS News. “I had enough of it.”

Mook figured out how the brothers could live with him instead of returning to foster care — “I slept the best I ever did that night,” Josh told CBS News of staying with Mook for the first time. And in September — seven years after he’d originally met the brothers — the Pittsburgh bachelor made it official and adopted Josh and Jessee.

“I’m very happy,” Jessee said after the adoption, according to Trib Total Media. “His house is clean, he has great rules, and I know he’s going to make me a better man in life.”