Chennai Additional Commissioner (North) Asra Garg confirmed the detention of the suspects. It has been reported that the suspects were thoroughly interrogated as well.

Meanwhile, Tamil Nadu BSP workers on Saturday staged a protest outside the Rajiv Gandhi Government Hospital in Chennai where postmortem of party's state unit president K Armstrong is being performed.

TN BSP chief hacked to death: All about the incident

• Armstrong on Friday was hacked to death by six unidentified people near his residence in Chennai's Perambur area.

• As per initial reports, a group of unidentified bike-borne assailants attacked Armstrong with knives which left him fatally injured on the road.

• A CCTV footage surfaced that showed that the accused fled the spot after killing Armstrong.

• Armstrong was promptly rushed to a private hospital in Chennai, where he was declared dead. Later, the dead body was was shifted to Rajiv Gandhi General Hospital for autopsy.

TM BSP chief murder: What did CM Stalin say?

Commenting on the incident, Chief Minister MK Stalin said he had ordered the police officers to bring the culprits to justice.

"Bahujan Samaj Party state president Armstrong's assassination is shocking and deeply saddening. The police have arrested those involved in the murder. I would like to convey my deepest condolences to all of Armstrong's party, family, relatives and friends who are bereaved, and I have ordered the police officers to conduct the case expeditiously and bring the culprits to justice as per the law," a rough translation of Stalin's tweet in regional language suggested.