The mugging may have taken place over three decades ago, but it's been weighing on Michael Goodman's conscience ever since.

So, when he randomly encountered his victim's name on Facebook, Goodman, 53, seized on the opportunity to apologize.

Goodman was a teen when he walked up to Claude Soffel on the steps of the American Museum of Natural History and mugged him.

Goodman was arrested for his crime by an undercover cop and sentenced to clean up subway graffiti, but he never saw Soffel again.

Fast-forward 35 years, and Goodman is reading a Facebook post about an H&H Bagels location being shuttered when he spots a familiar name.

"You may not remember this," Goodman wrote Soffel in the comments underneath the post, "but a long long time ago I walked up the steps of The Museum of Natural History one afternoon, trying to look like a tough guy to [somebody] & saw you standing there at the top of the steps, I walked up to you & (mugged) you for your bus pass."

"Finally I can say," he continued. "I"M VERY SORRY that you had to go through that crap that day long ago, I wish it had never happened but it did."

Goodman goes on to say that he was trying to prove to a friend that he was an honest-to-goodness gangbanger — a move he calls "pretty frickin' stupid."

Hours later, Soffel, now 52 and a life coach living in Sag Harbor, accepted Goodman's apology:

Michael A. Goodman, clearly your a "bigger man" today. wow. Memory is a funny thing, I recognize your name now, as well. So, apology accepted. Interestingly, I have dedicated a large portion of my life to helping other men be the man they have always wanted to be, and moments like this one continue to fuel my faith that the battle may be uphill but so rewarding. Any man who draws aline for himself, "Today I step forward for myself, my family, and humanity" is a hero to me. So let us now, jointly, put this in its proper place, behind us.

Goodman told the New York Post he's tried to make up for his bad deed by "doing good" ever since.

In fact, he was the recipient of a thank-you note from former NYC mayor David Dinkins after he bravely took down a man who attacked a woman near the building where he worked as a doorman.

"A very large weight has been lifted off my shoulder," Goodman replied to Soffel. "I feel peace and dare I say joy. I’m even happier this is bringing joy to other people."

[screengrabs via Facebook]