The police investigation was launched after mounting calls for a wider look into Bollywood's so-called "drugs mafia" following the suicide of actor Sushant Singh Rajput who was found dead in his Mumbai apartment in June.
Bollywood superstar Deepika Padukone has been summoned for questioning as part of an escalating drugs probe into the suicide of actor Sushant Singh Rajput.
The investigation has already seen actor Rhea Chakraborty arrested for allegedly buying drugs for her former boyfriend Rajput, who was found dead in June in his Mumbai apartment, with police saying he took his own life.
A star with many hit movies to his name, the 34-year-old's suicide initially triggered a debate over mental health in the multi-billion-dollar industry.
But his family disputed reports that he suffered from depression and accused Chakraborty, 28, of stealing his money and harassing him. She has been accused of driving Rajput to suicide by buying cannabis for him. Chakarborty has strongly denied the allegations.
Rajput's death has sparked a media storm in India, where calls have mounted for a wider probe into Bollywood's so-called "drugs mafia."
India's top anti-crime agency, the Central Bureau of Investigation, has been probing his death since last month. The Narcotics Control Bureau (NCB) was looking into his consumption of cannabis.
Earlier this week, TV channel TimesNow broadcast sections of a WhatsApp conversation about procuring hash, alleging that the two people chatting were Padukone and her manager.
KPS Malhotra, deputy director of the NCB, said the agency had summoned Padukone, as well as actors Sara Ali Khan, Shraddha Kapoor and Rakul Preet Singh for questioning.
The police have already detained others in connection with the case including Chakraborty's brother and a member of Rajput's house staff.
The investigation has grabbed headlines for months, and some celebrities including actors Vidya Balan and Sonam Kapoor have accused TV channels of carrying out a "witch hunt" against Chakraborty.
Born in the eastern state of Bihar, Rajput quit his engineering studies to pursue a career in acting.
He got his big break in 2013 with "Kai Po Che", a film about cricket, love, and politics that won acclaim at the Berlin film festival.
He was also lauded for his portrayal of Indian cricket hero Mahendra Singh Dhoni in a hit 2016 biopic.
In an interview with AFP that year, Rajput spoke of the emotional rollercoaster he experienced while filming the movie, which portrayed the heartbreak suffered by Dhoni when his girlfriend died.
"After we did the preparation, in my head I was him and everything that was happening was actually affecting me," he said.