We're learning about more trouble for a popular food chain...

FOX's Lilian Woo reports:

Chipotle getting served up a federal subpoena as part of a criminal investigation linked to a norovirus outbreak at its at one of its Simi Valley, California, restaurant back in August which sickened about a 100 people.

The court order received last month requires Chipotle to hand over several documents pertaining to eatery where the outbreak occurred. The restaurant chain calling the incident isolated saying it will cooperate fully with the investigation.

Chipotle still reeling from other food safety problems like the E. coli outbreak linked to its restaurants in late October and November and a separate norovirus outbreak at a Boston restaurant.

Lilian Woo, FOX News.