(CBSNEWS) – Two years ago, Officer Jody Thompson was pulling into the parking lot at the Poteau Police Department in Oklahoma to drop off his partner when he overheard a dispatch about a case of physical child abuse.

Thompson wasn’t on duty at the time, but he responded to the call and offered assistance. Before he joined the department 16 years ago, Thompson was an investigator for the district attorney’s office, where he handled dozens of abuse cases.

“I’ve investigated child abuse cases before,” Thompson told CBS News. “I thought I’d better go ahead and respond.”

When Thompson arrived at the scene, he was stunned to see a severely underweight boy — his wrists bound by belts, with bruises along his back and a huge knot on his head. The 8-year-old boy had been submerged in a trash can full of cold water.

He weighed just 61 pounds at the time.

“He did not have a spot on his body that didn’t have a bruise or abrasion,” Thompson said. “It was the worst thing I’ve ever seen.”

After covering the boy, who was named John, with a blanket, Thompson took him to an Oklahoma Children’s Advocacy Center so detectives and investigators could take photographs. When they were done, Thompson drove him to the emergency room.

“I sat with him,” Thompson said. “And when he was admitted into the intensive care unit, I sat all night until the next day.”

Poteau Police Department Officer Jody Thompson adopted an 8-year-old boy after responding to his child abuse 911 call. (POTEAU POLICE DEPARTMENT)

Thompson refused to let John out of his sight. He knew from the first moment he saw him he wanted to take care of him for the rest of his life.