Three more people, including an AIADMK functionary, were on Wednesday arrested by the CBI in connection with a case of sexual harassment of women by a gang in nearby Pollachi in 2019.
All of them were produced before the Mahila court, which remanded them to 14 days judicial custody, police said.
The central agency, which has taken over the probe from CB-CID, had already arrested five people in this connection.
A chargesheet was filed against the five arrested, in May 2019.
Further investigations led to the arrest of Arunanandam, the student wing leader of ruling AIADMK and his two friends in the early hours of Wednesday, they said.
The matter came to light in February 2019 after a 19-year old woman student had lodged a complaint with the police alleging that a gang of four men had tried to strip her inside a car, shot a video of the act and blackmailed her using the visuals.
The gang was believed to have sexually harassed and blackmailed a large number of women in Pollachi over a period of time.
The issue triggered public outrage, prompting the Tamil Nadu government to first transfer the case to the CB-CID police and then to the CBI.