Michael Berard, from Swansea in Massachusetts, said he was defrauded of $500,000 (£370,971) by two men, who called themselves Jack Murphy and George Adams, who have since vanished.
“These people took the money just as though they were John Dillinger or Billy the Kid,” he said.
“And they’re actually worse, cause when a guy points a gun at you, you know what you’re up against.”
After employing the pair for a small job, Berard said they told him he had a crack in his foundation.
“My whole adult life I’ve had struggles with anxiety, kind of walking the tightrope. At that point I think they sensed my anxiety and they said: ‘Mike, you’ve got a very big problem here. We need $15,000 (£11,124) right away’.”
And that was just the beginning. With Adams and Murphy convincing Berard that he would get his money back by suing the original builder of the house, he gradually handed over everything he had for needless work.
“They were like magicians. They were like Houdini and Copperfield and Blaine all rolled into one,” he said.
“What they said sounded so convincing.”
Berard has been unable to track down the two men.
BBC Spotlight also tried to find them, but could not reach them to ask about his allegations.
As well as Dinnigan, other members of the Travelling Conmen are now in custody, including Elijah Gavin who was jailed in November.