India's Narcotics Control Bureau (NCB) today issued summons to Bollywood actors Deepika Padukone, Sara Ali Khan, Shraddha Kapoor and Rakul Preet Singh in a drug link to the case filed in connection with the death of actor Sushant Singh Rajput.

Sara Ali Khan, Shraddha Kapoor, and Deepika Padukone. Photos: Collected

Deepika Padukone has been asked to appear before NCB on September 25, while Shraddha Kapoor and Sara Ali Khan have been asked to appear before the anti-drug agency the following day, KPS Malhotra, NCB deputy director, told Indian media.

On Tuesday, NCB had summoned Padukone's manager Karishma Prakash for questioning.

Padukone and the three other actors were allegedly named by actor Rhea Chakraborty, Sushant's girlfriend who was arrested by the federal anti-crime agency Central Bureau of Investigation in connection with his death, during her interrogation by NCB on September 6 and September 8.

NCB sources also said some WhatsApp conversations purportedly discussing drugs are on the radar of NCB.

Some of these chats were purportedly between Padukone's manager Karishma Prakash and one "D", they added.

During NCB's investigation into the drugs angle in the case filed over the death of actor Sushant Singh Rajput, a wider drugs dimension in Bollywood surfaced.

Rajput's talent manager Jaya Saha was questioned by NCB on Monday.

NCB has so far arrested more than 12 people, including Rajput's girlfriend and actor Rhea Chakraborty and her brother Showik Chakraborty, in connection with the drugs angle in the case relating to the actor's death.

Rajput (34) was found dead at his home in Mumbai's Bandra area on June 14.

The investigation into Rajput's death, his relationship with Rhea and the larger picture of alleged nexus between the Hindi cinema industry in Mumbai and drug mafia have grabbed headlines of the Indian TV channels for the last three months.