(IDEX Online) - Celebrity jeweler Joseph DuMouchelle, who twice auctioned the engagement ring given by Donald Trump to his second wife, has admitted masterminding a multi-million dollar gem fraud.He tricked a US businessman into investing $12m into a 77-carat diamond known as The Yellow Rose in 2019. DuMouchelle admitted via a videolink to the federal court that he withdrew most of the money and spent it. Prosecutors in Detroit, Michigan, believe another 26 victims gave him money or jewelry to sell, according to The Detroit News.DuMouchelle, son of the late famed auctioneer Lawrence DuMouchelle, pleaded guilty to wire fraud. Sentencing is expected in January 2021.In 2000, DuMouchelle, 58, owner of DuMouchelle Fine & Estate Jewelers, sold the 7.45-carat emerald-cut Harry Winston engagement ring (pictured) that Donald Trump gave to actress Marla Maples for $110,000. And then again in 2016 for $300,000 when the couple who'd bought it decided to sell.