Even Mr. Stackowitz’s longtime girlfriend, Cindy Derby, said she had no inkling of his history. “He never told anybody,” said Ms. Derby, 61, a house cleaner. “I’m glad I didn’t know because then I would have always worried. I didn’t have to worry for 21 years. It wasn’t any of my business.”

Mr. Stackowitz’s life took a decidedly wrong turn in 1966, when he was convicted of robbery by force in Georgia, where he had gone on a road trip. Court records show that, from crime to sentencing, the entire case lasted less than two weeks.

Ms. Derby said she was a 10-year-old schoolgirl in Sherman when Mr. Stackowitz was arrested in Georgia. An indictment accused him and two other men of “unlawfully, wrongfully, fraudulently and violently” stealing $9 from a man, as well as the keys to his truck. The victim, now 91 and still living in Georgia, did not respond to an interview request.

On Aug. 22, 1968, Mr. Stackowitz escaped from what was once known as the Carroll County Convict Barracks, a project built as part of the New Deal that is now a dilapidated storehouse for the county’s Public Works Department. The words “Carroll County” are painted in red near the roof, but the doors are rusted, and the paint on the prison bars is peeling and cracked.

Mr. Stackowitz, who agreed to be photographed but declined an interview request, has told reporters that he had access to a vehicle as part of his work duties at the prison, where he repaired buses nearby.

“One morning I just got in the truck and drove myself away,” he told The Hartford Courant in a videotaped interview. “I got on a plane and I was back in Connecticut before they even knew I was gone.”