Major League Baseball has opened a formal investigation into illegal gambling and theft allegations involving Los Angeles Dodgers star Shohei Ohtani's interpreter, Ippei Mizuhara.Mizuhara was let go from the team Wednesday following reports from the Los Angeles Times and ESPN about his alleged ties to an illegal bookmaker."Major League Baseball has been gathering information since we learned about the allegations involving Shohei Ohtani and Ippei (Mizuhara) from the news media," the commissioner's office said in a statement Friday. "Earlier today, our Department of Investigations began their formal process investigating the matter."Ohtani and the Dodgers were in Seoul, South Korea, for their opening series against the San Diego Padres when reports were published about alleged ties between the 39-year-old Mizuhara and an illegal bookmaker. The teams returned to the U.S. after Thursday night's game and MLB did not make a public comment until announcing the investigation on Friday.The IRS confirmed Thursday that Mizuhara and Mathew Bowyer, the alleged illegal bookmaker, are under criminal investigation through the agency's Los Angeles Field Office. IRS Criminal Investigation spokesperson Scott Villiard said he could not provide additional details.