SIOUX FALLS, S.D. (KELO) — There have been a number of deadly school shootings across America, one of the latest was in Ulvade, Texas.

But a janitor from Dakota Wesleyan University thinks he’s invented a device that could save lives and make him a rich man.

When he’s not cleaning floors, DWU janitor Jeff Harris is mopping on new ideas and things to invent.

“I’ve had other ideas in the past that I did not capitalize on and those inventions that I’ve had in my mind have come true and other people have gotten them,” Harris said.

But this time he decided to follow through on it.

Two years ago during an active shooter training session on campus, Harris got an idea of how to lock doors to a classroom if there was ever an active shooter in the building.

“I thought of it, and within an hour I had this idea and within another hour, assembled it,” Harris said.

Last Thursday he finally was awarded a patent for the Threat Stop.

“The active shooter training folks, they said they’d never seen anything like it on the market and you’d better patent that or else we’re going to,” Harris said.

Harris demonstrated it for us to show us how it works.

“If the person breaks out the window, they can’t get the lock off,” Harris said.

That’s because of two little stainless steel mechanisms that an active shooter wouldn’t be able to reach.

Obviously, not all doors are made the same. This one is a crash bar, but Harris has two other patents pending. One for a door with levers and the other for a door with knobs.

Harris says he’s illiterate; he can barely read or write, but he knows how to solve problems and his latest invention could potentially save lives.

“That’s what it’s all about to save lives it’s not about the financial it’s about saving people’s lives and protecting them from harm, that’s where the Threat Stop comes in,” Harris said. “Being a firefighter and EMT for 30 years just trying to help protect people from bad situations.”

Harris says he wants to sell the patent and is currently negotiating with a few companies that have shown an interest in buying the patent for the Threat Stop.