The Malayalam actor is being interrogated in Aluva area of Ernakulam district.
On November 3, the actor sought a Central Bureau of Investigation (CBI) enquiry into the case.
He was granted bail on October 3 after the actor deposited his passport and furnished a surety bond of Rs 1 lakh.
The actress, who has worked in Malayalam, Tamil and Telugu films, was kidnapped and molested in a moving car while she was on her way from Thrissur to Kochi on the night of February 17 this year.
Dileep was arrested on July 10 because of his alleged involvement in the molestation case. Following the arrest, he was also expelled from the primary membership of Association of Malayalam Movie Artists (AMMA) on July 11. (ANI)