So when they discovered that same father had been robbing small-town banks, the three sons put his tutelage to the test: They turned him in.
Now William Alfred "Al" Ginglen, a 64-year-old grandfather of seven, could spend the rest of his life in prison. He pleaded guilty in July to seven counts of armed bank robbery and two counts of carrying and using a firearm during a crime of violence; sentencing is scheduled Thursday in federal court in Springfield.
His sons say they have no regrets.
"He turned to crime, and we had an opportunity to stop it," said Clay Ginglen, 36, a music teacher in his hometown of about 2,600 people. "He was robbing banks with a gun. He could have easily hurt anyone: a bank teller, a policeman. He could have been hurt as well."
Ginglen's double life, which authorities allege included a girlfriend, drugs and prostitutes, started to unravel in August 2004, when one of his sons, Peoria police Officer Jared Ginglen, looked at surveillance videos posted on a law enforcement Web site and recognized his dad behind sunglasses, a dust mask and driver's cap.
He called brother Garrett Ginglen, 41, a Caterpillar Inc. engineer, who says he broke into a sweat and threw up in his office trashcan when he called up the photos.
"I felt like if I could I would get up and run as fast and far as I could," he said. "Just trying to get away from it and pretend like it didn't happen."