The mystery man behind an anonymous Twitter account who has been tweeting clues to hidden envelopes of cash around Washington and Baltimore revealed his identity Thursday.

Turns out, his weeks-long project, which has so far cost him more than $1,000, all started as a way of proving his boss wrong.

Marc Orem, a radio host who goes by Marco on his morning show on 107.3 FM, revealed himself as the benefactor behind the account in a post on Thursday. His story, he said, started on the day he heard his boss tell him that he was too old to understand social media.

Orem, 37, is a father of four who lives in Urbana, Md. He has not tweeted from his personal account since December. But he felt sure he could be a hit on social media if he tried.

From that provocation, @IHidTheCash, inspired by a similar giveaway account in California, was born.

“I’m glad he said it,” Orem said about his boss’s gibe. “It was my a-ha moment. And I’m glad it worked out the way it did.”

In the past seven weeks, he has tweeted 1,391 times — mostly clues to the envelopes containing $20 to $60 each that he hid around the region and exhortations to finders to do some good for others with the money. He has accumulated 9,178 followers. He has given away money about 30 times.

He said he never considered telling his boss about his idea or running his cash giveaways through his radio station. First of all, he didn’t want the hassle of vetting the project with corporate lawyers. Moreover, he thought that the blend of his social service message and his radio persona might be jarring.

“The first second I give a frequency or give call letters, boom. This is a plastic, Styrofoam radio stunt,” he said. “I’m proud of the radio station I work for, but this is just such a separate project for me.”

After dropping his disguise Thursday, Orem said that he thinks almost all the finders have donated the cash to charities or to people they know who are in need.

He said he has also heard from at least a dozen organizations who noted his social media savvy and asked him to help them out with their own social-action-oriented online projects. He would not name the organizations since he has not started working on projects with them, but he plans to talk to several of them about how he can help.

At the same time, he’ll keep giving away money just as he has been, he said.

Now that his identity is known, though, he thinks the quest might feel a little different for some of his loyal followers.

“I think some people really got into the mystique — who was this person? Why are they doing it?” he said. “I’ve never, like, dated online, but I guess it may be like when you finally meet in person for the first time at a restaurant or a bar.”

He feels he has proven his point: “There’s a mystique that you have to be 16 years old to understand social media, which is stupid. Like if you don’t have a neck tattoo you don’t understand Snapchat.”