The interrogation continued from 6 pm to 1 am on Thursday.
As a part of investigation a room in his ashram Divya Dham in Shahjanapur was sealed by Special Investigation Team (SIT), his lawyer Om Singh said.
However, a police official was quoted as saying: "All the rooms in the ashram have been sealed and only one room has been left open. A heavy deployment of force has been made outside the ashram. Forensic teams are being called in to take evidences from the bedroom of the accused and other rooms," by news agency IANS.
Late on Thursday, the SIT interrogated the BJP leader at the reserve police lines here in Uttar Pradesh. Chinmayanand was accompanied by his lawyer Om Singh.
Earlier on Thursday, SIT had recorded the statement of SS Law College Principal Sanjay Kumar Baranwal and Secretary Avanish Misra.
SIT sources had on Thursday that summon had been sent to Chinmayanand for questioning but the former Minister did not appear citing health reasons.
According to reports, Chinmayanand was interrogated on the allegations leveled by the law student, as well as on a video clip showing him getting a massage by a girl.
The 72-year-old reportedly denied the allegations and claimed that he was being asked for money by some boys and when he refused to pay, they hatched the conspiracy against him.
On August 24, the law student had posted a video on Facebook in which she alleged the former Union Minister had exploited many girls, including her. She also claimed to possess proof against Swami Chinmayanand. After posting the video, she went missing.
On August 25, Shahjahanpur police filed an FIR on the complaint of Chinmayanand's lawyer Om Singh under the sections of extortion and Information Technology Act against unidentified persons.
Later, police lodged another FIR under IPC section 364 (abduction with intent to commit murder) and 506 (criminal intimidation) against Chinmayanand and unidentified persons on August 27.
However, Chinmayanand was not summoned or arrested by police.
On August 30, the student was found in Rajasthan's Dausa district.
A team of Uttar Pradesh Police recovered her from a hotel near Mehandipur Balaji temple in Dausa and produced her in the Supreme Court on same day as per the apex court's directives.
The top court later ordered an SIT probe into her allegations. A special bench of the Allahabad High Court is monitoring the SIT probe.
(Additional inputs from IANS)