Biogenesis whistleblower Porter Fischer turned over much-anticipated documents while appearing at a grand jury in Miami in the past week, according to ESPN.
Major League Baseball tried for months to get Fischer to release the records in its effort to investigate the now-defunct clinic.
Fischer leaked some of the records to the Miami New Times last year, which began a performance-enhancing-drugs scandal that led to 14 major league players being suspended.
MLB investigated Biogenesis after the stories broke that players were connected to the clinic and obtained PEDs from it.
New York Yankees third baseman Alex Rodriguez is appealing a 211-game suspension. Milwaukee Brewers outfielder Ryan Braun accepted a 65-game ban. Twelve other players, including Texas Rangers outfielder Nelson Cruz and Detroit Tigers shortstop Jhonny Peralta, are serving 50-game suspensions.
Fischer's grand jury appearance is an indication that the scandal will result in a federal law enforcement investigation that may lead to criminal charges against those linked to the clinic, including founder Tony Bosch. Players may be questioned or called as witnesses but will likely not face charges.
Some of the 800-plus pages of documents that Fischer turned over date back to 2009. The records detail doping regiments for pro athletes but law enforcement officials are likely more interested in documents related to underage athletes, Bosch's false references to him being a doctor and spreadsheets that show payments made to deliver drugs.
Fischer and his lawyer refused to comment but MLB officials said Thursday that they are aware of the grand jury proceedings.
Fischer was not questioned under oath, but he may be called back to clarify details in the documents.
The federal investigation has reportedly intensified recently but the Drug Enforcement Administration had already started interviewing sources and getting clinic records.
MLB tried to get Fischer to cooperate with its investigation, even offering him $125,000, but Fischer refused because he felt bullied. MLB named Fischer in an emergency court order earlier this month, which asked a Miami-Dade Circuit Court to require him to release his records.
Bosch has been cooperating with MLB since it filed a local civil lawsuit in March against him and five others connected to Biogenesis. MLB promised to release Bosch from the suit if he cooperated with its investigation.
One key witness is Lazaro "Lazer" Collazo, a former University of Miami baseball coach, who is scheduled to be deposed Friday. Collazo was a Biogenesis patient who is referred to in Biogenesis documents, including his two then-teenage sons being treated by Bosch.