Chipotle Vows to ‘Cooperate Fully’ With Criminal Probe of Virus Outbreak

— -- Federal authorities have opened a criminal investigation of Chipotle Mexican Grill after a norovirus outbreak in California that led to at least 234 people being sickened, according to a U.S. Securities and Exchange Commission filing.

The company has come under fire recently after multiple norovirus and E.coli outbreaks last year were linked to the Denver-based restaurant chain, including one E.coli outbreak that sickened at least 53 people in multiple states.

The company noted in a filing today with the SEC that it has been served with a federal grand jury subpoena and is being investigated by the U.S. Attorney’s Office for the Central District of California, in conjunction with the U.S. Food and Drug Administration’s Office of Criminal Investigations.

The investigation is focusing on the norovirus outbreak at a Chipotle restaurant in Simi Valley, California, according to Chipotle’s Jan. 6 “current report,” or Form 8-K, that companies file with the SEC to alert shareholders about major events.

That outbreak led to at least 234 people being sickened, according to a memo from the state Environmental Health Division.

The company’s report does not go into detail about the investigation.

The subpoena will require the company to produce "a broad range of documents," according to the SEC filing.

A company spokesman declined to respond to the legal action.

"As a matter of policy, we don't discuss pending legal action, but we will cooperate fully with this investigation," Chipotle spokesman Chris Arnold told ABC News.

The FDA released a statement but did not comment directly on the case because of the ongoing criminal complaint.

"When foodborne illness outbreaks occur, the FDA works closely with other federal and state agencies and other health officials to identify the source, ensure that companies are removing affected foods from the marketplace, and communicate with the public," the FDA said in a statement to ABC News today. "No system is foolproof, but the FDA works to prevent as many foodborne illness outbreaks as possible."

The U.S. Attorney’s Office declined to comment, citing a policy not to comment on ongoing criminal investigations.

ABC News' Aaron Katersky contributed to this report.