Widening its probe into the drugs angle in the death of Bollywood actor Sushant Singh Rajput, the Narcotics Control Bureau (NCB) will summon Bollywood actors Sara Ali Khan and Shraddha Kapoor for questioning.A top NCB source related to the probe told IANS: "This week, we will be sending summons to Sara, Shraddha and several others for questioning."Besides them, the NCB will also summon actor Rakul Preet Singh and fashion designer Simone Kambhatta. He said that the agency will ask them to join the probe next week.Sara starred with Sushant in "Kedarnath" while Shraddha shared the screen with the late actor in "Chichhore".An NCB source said that the drug law enforcement agency got the lead on these actors after it was found that they went on an island near Pune multiple times for parties.The NCB has arrested Sushant's girlfriend Rhea Chakraborty, her brother Showik Chakraborty, Sushant's personal staff Dipesh Sawant and several others in the case for allegedly procuring and transporting drugs.It had registered a case on a request from the Enforcement Directorate (ED) after it found several WhatsApp chats between several people ostensibly for procuring drugs.