Joan Rivers' death is being linked to death threats. According to a report from thehill.com, FBI revealed messages that were sent to the late "Fashion Police" host.

Death threats recorded by the FBI were exposed eight months after Joan Rivers' untimely death. The notoriously frank comedienne passed away last Sept. 4  following a botched throat operation at an Upper East Side medical facility called Yorkville Endoscopy.

Joan Rivers was 81 years old at the time of her death.

The veteran comedienne has been known for her notoriously frank jokes. However, a joke that she made about Polish culture during a 1973 performance in caused a hater to send a threatening Western Union telegram.

"Perhaps ... I can teach you the difference between a joke and an assault on human dignity and decency," the letter started.

"My people will no longer sit back supinely while a human cesspool spews her dirt on them. And for a Jewess you should know better."

The sender demanded the late "Fashion Police" star to stop making controversial jokes. The sender added that he or she will "put a stop" to everything.

FBI also revealed letters sent to Joan Rivers from 1991 containing death threats.

The taunts were from somebody who hid with the name "Mr. Clean," who said he did not like Joan Rivers' "Jew Humor."

"Others will then be able to follow the path that I started and complete my mission of righteousness... I am looking for just the right time and place to destroy you and your Jew Humor," the hater wrote.

Other death threats were also sent to the former "Fashion Police" host via phone calls.

Joan Rivers was supposedly interviewed by FBI agents about the death threats, who explained that the taunts did not break any federal laws.

"(FBI recorded the incident) in view of Rivers' prominence as (a) public entertainer," the federal officials explained.

"It was noted that Rivers has hired off-duty Miami Beach PD patrolmen to stand guard at the entrance to her suite."