The reeling Chipotle restaurant chain had more bad news for investors on Wednesday, announcing it has been served with a federal grand jury subpoena as part of a criminal investigation tied to a norovirus outbreak this summer at one of its restaurants in California.
The investigation, which is being conducted by the U.S. Attorney's Office for the Central District of California in conjunction with the Food and Drug Administration's Office of Criminal Investigations, involves an outbreak at a restaurant in Simi Valley in August 2015, the company said in a filing with the Securities and Exchange Commission Wednesday.
Chipotle Mexican Grill said the subpoena requires it to produce a "broad range" of documents and that it intends to fully cooperate with the investigation.
The Simi Valley norovirus outbreak, initially reported to have sickened 98 people, actually made 234 people ill, Food Safety News reported last month, citing Ventura County Public Health documents. The report said that an inspection of the restaurant shortly after the outbreak found numerous safety violations, including failures in pest control, sanitation, and maintenance. Employees also were working without valid food handler cards as required by California law, according to the report.
The Denver company has been reeling since an E. coli outbreak in October linked to its restaurants, which was followed up by a separate norovirus outbreak in Boston.
In its SEC filing, Chipotle says it expects sales for the fourth quarter to be down 14.6 percent and that sales in December were down 30 percent on persistent media reports on the food-borne illnesses.
This story originally appeared on NBCNews.com