Late Bharatiya Janata Party leader Pramod Mahajan's son Rahul was arrested this evening for allegedly consuming drugs and destroying evidence, three days after he was hospitalised in a critical condition.

His father's key aide Bibek Maitra had died on his way to the hospital.

31-year-old Rahul was placed under arrest in the hospital after nearly four hours of sustained interrogation.

He has been booked under various sections of the Narcotics Drugs and Psychotropic Substances Act including consumption of drugs and use of residence for the purpose. If found guilty, he can face a jail term up to one year and fine of Rs 20,000 or both.

"We have arrested him on the basis of totality of evidence. We have sufficient evidence against him," Additional DCP Manish Agarwal told reporters outside the hospital.

"We have enough witnesses and statement to prove that he took drugs on Thursday night," he said adding that the police want to take him in custody as soon as possible for further interrogation.

Agarwal said they were seeking the opinion of doctors to have him discharged.

Police earlier arrested Sahil Zaroo, who allegedly bought drugs for Rahul and Maitra, and three Nigerians drug peddlers on charges of supplying drugs.

"He has said a lot of things. He spoke well and was cooperative. But sharing the things with you would not be proper," Agarwal told PTI when asked about the details of interrogation by senior police officials during the day.

Investigators also questioned six Apollo doctors, including Medical Director Anupam Sibal, at the Tughlaq Road police station to 'piece together the sequence of events which took place after his admission to the hospital'.

In a bid to find out what transpired at Mahajan's 7, Safdarjung Road house during the small party on the fateful night of June 1, police also interrogated Harish Sharma, a key aide of Pramod Mahajan.

They confronted Sahil with three other persons -- Karan Ahuja, Trishay Khanna and Rahul Malhotra -- who were also present during the small gathering, to substantiate the statements given by them.

In another significant development, the Central Forensic Sciences Laboratory said the white powder pouch handed over to them by the police for testing contained heroin.

"The 1 inch by 1.5 inch red pouch handed over on June 2 contains heroin," a CFSL communiqu� to the Delhi police said.

Rahul has to be produced within 24 hours of arrest before a magistrate who would decide whether to remand him to police or judicial custody.

When asked how the police will go about doing this, Delhi Police Commissioner K K Paul was non-committal and told rediff.com: "We will take a decision when the time comes."

With PTI inputs