Rivers went to Manhattan’s Yorkville Endoscopy for a routine endoscopy, which means a camera was put down her throat to check on her vocal cords. The clinic's medical director Dr. Lawrence Cohen performed the procedure. Then, according to a source, Rivers’ personal ear, nose, and throat doctor performed a biopsy, meaning he took a small sample of cells from her vocal cords, without Rivers’ prior consent. That doctor wasn't legally certified to perform a biopsy in that clinic. Investigators believe that Rivers’ vocal cords began to swell during the biopsy, cutting off the flow of oxygen to her lungs, leading to the cardiac arrest. The legend was rushed to the hospital but it was too late. She never regained consciousness, and passed away a few days later, on September 4, when she was taken off of life support.