Joan Rivers' Doctor's Office, Yorkville Endoscopy, Under Investigation

The clinic where Joan Rivers was undergoing a procedure prior to her hospitalization is now under investigation.

The New York State Health Department told ABC News that it has opened a "full investigation" into Yorkville Endoscopy Center in New York City to determine whether the clinic would be cited for violations.

Investigators have already visited the clinic.

There are certain types of incidents that must be reported to the state and the events surrounding Rivers' emergency was one of those, though health officials declined to elaborate what specifically triggered the investigation. More