As of now, there is no suspicion of wrongdoing and the investigation is routine, a source briefed on the case told ABC News. The investigation was triggered automatically by a complication during a procedure at an outpatient clinic, the source added.
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.
Yorkville Endoscopy was established in 2013 and was inspected by the State Health Department prior to opening. To date, there have been no complaints or violations regarding the facility.
A woman who answered the phone at the clinic Thursday told ABC News the clinic had no comment.
[Editor's note: The clinic released the following statement a day later, on Friday: “HIPAA laws prevent us from disclosing any information about patients. In the event of an adverse incident, Yorkville Endoscopy would promptly report to appropriate government and regulatory agencies and would proactively cooperate with any governmental review.”]
Rivers, 81, was taken to Mount Sinai Hospital in Manhattan on Aug. 28 after an emergency call reported she was in cardiac arrest at Yorkville Endoscopy, a source told ABC News.
Rivers had been unconscious and sedated since her arrival at Mount Sinai, but died today.
Last week, her daughter, Melissa Rivers, confirmed that the comedian was on life support.
ABC News's Patty Neger contributed to this report.