It's a great story so reposts aren't that frustrating, but the Daily Beast reporting in 2018 is better researched and wildly entertaining: https://www.thedailybeast.com/how-an-ex-cop-rigged-mcdonalds...
More realistically, at least one of Jacobson's friends or family couldn't keep their mouth shut that Jacbson worked for the promotion. An associate of theirs was connected to Columbo and decided to extort Jacobson.