Dan Donovan said a man posing as a utility worker knocked on the door of the house he and his wife, Barbara, occupy in the suburb of Niles in the north of the city claiming he needed to check their fuse box following a recent fire.

“We had received a letter from the electric company the day before, so when he said he was with the electric company, we let him in,” he told the Chicago Tribune.

Speaking to the paper about the November 4 incident, Barbara Donovan said: “I kept backing up and he kept saying, ‘come over by me.’ He said, ‘if you’re home alone, you won’t know what to do,’ and kept telling me to come closer to him. I thought that was kind of weird.”

While the man was in the basement with the couple they heard floorboards creaking overhead. “I hear the floor in the bedroom squeaking and I yelled Dan! Dan! Somebody’s in our bedroom!” she said.

They ran upstairs followed by the man and found two other men emerging from their bedroom holding a pillowcase.

Dan Donovan chased the three men out of the house, grabbing his grandfather’s antique Irish walking stick as he went.

“I was trying to find some type of persuasive weapon,” he told the Tribune. “So I picked up the Irish shillelagh and that turned out to be the equalizer because I managed to chase them out of the house.”

Speaking to Fox 32, he added: “It’s 100 years old. So if I hit him with this, it’ll make a point.”

The former marine, who was barefoot, struck the man carrying the pillowcase on the back of the head with the stick before chasing the group of men onto the road.

“I hit the guy in the head. I’m certain I got him in the head good because he wouldn’t let go of the pillowcase,” he said.

“Hopefully they got nothing more than a headache and hopefully they pursue another occupation.”

He repeatedly struck the windscreen and rear window of the men’s SUV before they fled.

“I’ve never heard him speak like that. He said I got the one guy, I got the one guy right in the head. I said ‘good, good,’” Barbara Donovan added.

Police were said to be still looking for the men after receiving reports of a number of similar robberies involving suspects posing as utility workers in the Chicago suburbs.