On Tuesday, art director Dharma Rao appeared before the Special Investigation Team (SIT) probing the racket.
SIT officials began questioning him at around 10.30 a.m., at Abkari Bhavan, the office of Prohibition and Excise Department.
Rao is the sixth artist from Tollywood to be questioned in the case.
SIT officials on Monday grilled actor P. Navdeep for over 11 hours.
The investigating team has summoned 12 celebrities for questioning as their contact numbers were found in the call data of Calvin Mascrenhas, the kingpin of the racket.
Actors Tarun and Subbaraju, director Puri Jagannadh and cinematographer Shyam K. Naidu were interrogated last week.
Actors Ravi Teja and Nandu, actresses Charmme Kaur and Mumaith Khan are among the other celebrities who will be questioned this week.
Charmme Kaur’s petition seeking direction to SIT not to compel her to give samples of body fluids, hair and nails is scheduled to come up for hearing in Hyderabad High Court later in the day.
Enforcement, Prohibition and Excise Director Akun Sabharwal on Monday clarified that the SIT is collecting the samples only with the written consent of the persons questioned.
The SIT has so far registered seven cases and arrested 19 accused. It has questioned a total of 28 people.
The case took a new turn on Monday when SIT arrested manager of leading actress Kajal Aggarwal.
Puttkar Ronson Joseph was arrested from his house in Manikonda here. Narcotic substances were recovered from his possession.
The department has so far recovered 3,000 units of LSD, 105 grams of MDMA, 45 grams of cocaine and other narcotic and psychotropic substance.