The New York state health department is investigating the circumstances surrounding Joan Rivers' cardiac arrest during a routine procedure at a Manhattan doctor's office last week.
Spokesman James O'Hare said the department is looking into "the whole matter", declining to discuss specifics.
Rivers was rushed to hospital after the complications during surgery, and died today aged 81.
Here are 10 of the sharpest one-liners from Joan Rivers, who has died aged 81.
Stars have paid tribute to comedian Joan Rivers as fans lay flowers on her Walk of Fame star and comedy venues show their respect.
A pioneer in the world of comedy, Joan Rivers carved a career with her tenacity and an acid tongue that spared no-one - including herself.