"Then I saw a bag under there and pulled it out," he told Newshub.
Seeing a flash of red as he opened the bag, he thought, 'shit, there's money in there,'" he said.
Derecourt later counted out dozens of $100 notes.
"I thought what the hell am I going to do?"
He told Newshub it was a challenge to do the right thing, as money was tight.
But he called up the "gobsmacked" owner of the money, who later came to pick it up, Newshub reported.
"He began telling me about how his wife had been really sick and died of cancer and it was really emotional," Derecourt said.
The man told Newhub he was "very grateful" to have the $5000 returned.
"I'm very, very grateful," he said.
"Absolutely there are some good people out there … he deserves recognition for the act he did."
He's put the stack of cash in the drawer "for a rainy day" but had forgotten about it, he said.
Derecourt said the man gave him a "couple hundred bucks" when he collected the money, as well as bringing chocolates and posters for his two children.