An anonymous phone caller has threatened to kill Bollywood superstar Salman Khan, prompting the Mumbai Police to launch a probe, an official said on Tuesday.The phone call was made to the city’s Police Control Room on February 16, police said. Police suspected it was a hoax call and launched a probe though no case has been filed yet.Police has managed to locate the place from where the call was made.Salman Khan has recently delivered two back-to-back hits with ‘Prem Ratan Dhan Payo’ and ‘Bajrangi Bhaijaan.’ The actor is currently working on his next film Sultan.