SYDNEY - Death threats have been made against the Australian radio hosts involved in the royal prank call tragedy, police said Friday, with station management reportedly moving some staff to safehouses.The revelations came as a London inquest showed the nurse who fielded the hoax call, Jacintha Saldanha, 46, hanged herself.The mother-of-two was found dead last Friday, three days after transferring the call to a colleague who divulged details about Prince William’s pregnant wife Catherine who was recovery from severe morning sickness. Saldanha was discovered in nurses’ quarters near the private King Edward VII’s Hospital in central London where Kate was being treated. She also had wrist injuries and left three notes. Australian police have launched an investigation into the death threats after a letter targeting presenter Michael Christian was seized, warning him there were “bullets out there with your name on it”.The letter was obtained by Sydney’s Daily Telegraph, which said further threats were made involving a shotgun which it said were inappropriate to print. The Australian Broadcasting Corporation said staff at 2Day FM’s parent company Southern Cross Austereo have been receiving threats all week. “Police are conducting an investigation into threats made against two Sydney radio presenters,” a New South Wales police spokesman told AFP. “Detectives seized a letter which contained a number of threats. Detectives are conducting an investigation into the matter and are attempting to identify the source of the letter.” The Telegraph said about a dozen staff at the broadcaster have been moved to hotels for their safety and up to 10 executives have been assigned bodyguards. Southern Cross Austereo would only say that “the safety of our employees is an absolute priority”. “We have sensible measures in place, as we always do, to ensure our people are safe,” a spokeswoman told AFP. Christian and fellow host Mel Greig, who have been undergoing counselling, remain off air and have not been seen in public since making tearful apologies in a television interview on Monday. It follows the pair posing as Queen Elizabeth II and William’s father Prince Charles in a hoax call to the hospital, which sparked an outpouring of global anger against them. Senior British police officer James Harman told the inquest there were “no suspicious circumstances” surrounding Saldanha’s death.