The Worli police have registered a case under Bharatiya Nyaya Sanhita (BNS) for threat and extortion. The city's traffic control room on Thursday afternoon received a threat on its WhatsApp helpline, he said. In the message, the sender threatened the actor and demanded Rs 5 crore from him, he said, adding that a probe is underway. The superstar had earlier received death threats from the Lawrence Bishnoi gang. Bishnoi gang members had also opened fire outside the actor's Bandra home in April, he said. Meanwhile, the Navi Mumbai police on Thursday uncovered a plot to kill Khan by the Bishnoi gang in June and arrested one of its shooters, identified as Sukhbir Singh of Haryana's Panipat, he said.