LOS ANGELES (AFP) — Major League Baseball announced a formal investigation into the scandal swirling around Shohei Ohtani and his former interpreter amid charges the Los Angeles Dodgers superstar was the victim of "massive theft."

The Dodgers fired Ippei Mizuhara, Ohtani's long-time interpreter and close friend, on Thursday after Ohtani's representatives alleged the Japanese two-way star had been the victim of theft, which was reported to involve millions of dollars and link Mizuhara to a suspected illegal bookmaker in California.

"Major League Baseball has been gathering information since we learned about the allegations involving Shohei Ohtani and Ippei Mizuhara from the news media," MLB said in a statement.

"Earlier today, our Department of Investigations began their formal process investigating the matter."

ESPN reported that MLB is expected to request interviews with all parties, including Ohtani and Mizuhara, although officials cannot compel Mizuhara's cooperation because he no longer works in the major leagues.

The murky affair emerged this week when West Hollywood law firm Berk and Brettler issued a statement on behalf of Ohtani after receiving media inquiries about a reported federal investigation into alleged illegal bookmaker Mathew Bowyer in which Ohtani's name surfaced.

"In the course of responding to recent media inquiries, we discovered that Shohei has been the victim of a massive theft and we are turning the matter over to the authorities," the law firm said.