(AP) -- The head of the outpatient surgery facility where Joan Rivers went into cardiac arrest during a routine procedure is no longer at the clinic.

A spokeswoman for Yorkville Endoscopy said Friday that Dr. Lawrence Cohen is no longer the facility's medical director, nor is he performing procedures there.

The spokeswoman did not elaborate on the circumstances surrounding Cohen's departure.

Cohen, a respected gastroenterologist, did not return telephone messages. An email to Cohen's account at Mount Sinai Hospital bounced back.

Rivers died Sept. 4 at Mount Sinai Hospital, a week after going into cardiac arrest. The sharp-tongued comedian, talk show host and fashionista was 81.

The state health department has said it's investigating "the whole matter." A spokesman for the department did not immediately have an update on the investigation Friday.

The city medical examiner's office is also investigating. A spokeswoman for the office said this week that a determination on the cause and manner of Rivers' death are pending further studies.

Cohen has been listed in New York state records as a co-owner of Yorkville Endoscopy.

He has taught at the Mount Sinai School of Medicine, contributed to more than 150 books and articles on gastroenterology and lectured on various topics, including colorectal cancer screening and endoscopic sedation, according to a biography posted on the clinic's website.

There are no disciplinary actions on Cohen's record and his license is current, according to state records.

A Mount Sinai spokesman said Cohen no longer teaches there, but still has a professional relationship with the hospital.

"Dr. Lawrence Cohen is a voluntary physician with admitting privileges at The Mount Sinai Hospital," spokesman Sid Disnay said. "He maintains a private practice."