An Orange County resident was sentenced to one year and one day in federal prison for operating an illegal sports-betting business and failing to report income on his taxes. Mathew R. Bowyer, 50, of San Juan Capistrano, received the sentence from United States District Judge John W. Holcomb, who also ordered him to pay $1,613,280 in restitution.
Bowyer pleaded guilty in August 2024 to charges including operating an unlawful gambling business, money laundering, and filing a false tax return. According to court documents, Bowyer’s bookmaking operation ran for at least five years until October 2023 and served more than 700 bettors at times.
Prosecutors stated: “[Bowyer’s] crimes were not a single indiscretion, but instead a multi-year operation that raked in millions of dollars for [Bowyer] and his associates to gamble and live an extravagant lifestyle, often through the exploitation of people [Bowyer] recognized were addicted and extending themselves beyond their means, money that was routed through multiple accounts and ultimately not reported to the government on [Bowyer’s] taxes.”
The illegal betting business operated out of locations in Los Angeles County, Orange County, and Las Vegas. Bowyer employed agents—including casino hosts—who received commissions based on bettors’ losses. The business used Costa Rica-based websites and a call center for placing bets. Some agent payments were made with casino chips.
One client identified in court was Ippei Mizuhara, the former Japanese-language interpreter for Major League Baseball player Shohei Ohtani. Mizuhara is currently serving a 57-month federal prison sentence after pleading guilty in June 2024 to bank fraud and subscribing to a false tax return. He admitted stealing nearly $17 million from Ohtani to cover gambling debts.
Between September 2021 and January 2024, Mizuhara placed over 19,000 bets with Bowyer’s operation using online platforms associated with the business. During this period he had total winning bets exceeding $142 million and losing bets surpassing $182 million—leaving him owing approximately $40 million.
From February 2022 through January 2024, Bowyer instructed Mizuhara to send at least $16.25 million in gambling proceeds to Bowyer-controlled accounts. Of these funds, more than $9 million was wired directly to a casino as payment for markers for Bowyer and his associates.
Other customers included professional athletes such as “Individual B,” a current Southern California baseball player, and “Individual C,” a former minor-league player.
In addition to the illegal gambling activities, Bowyer underreported his taxable income by over $4 million on his 2022 tax return—declaring only about $608,000 when he actually earned more than $4.6 million that year from the illegal enterprise. As a result of submitting false information on his tax return for that year alone, he owes over $1.6 million in additional taxes before interest or penalties are applied.
As part of his plea agreement with prosecutors, Bowyer agreed to forfeit more than $257,000 in cash along with nearly $15,000 worth of casino chips seized during law enforcement action in October 2023.
The case was investigated by IRS Criminal Investigation and Homeland Security Investigations. Assistant United States Attorneys Kristen A. Williams (Major Frauds Section) and Jonathan S. Galatzan (Asset Forfeiture and Recovery Section) prosecuted the case.
