Security agencies were put on alert on Friday after an email threatened to blow up Bollywood actor Amitabh Bachchans Mumbai residence, the Bombay High Court and the Mahalaxmi Racecourse. The threat was subsequently declared a hoax, according to police, News18 reported. nbsp;The email named Bachchans Juhu bungalow, Jalsa, along with the Bombay High Court and the Mahalaxmi Racecourse, where singer Diljit Dosanjh is scheduled to perform later this month.