An accused in the murder of Tamil Nadu BSP leader Armstrong was killed by the Chennai police in an extrajudicial murder (commonly known as encounter). The suspect, K Thiruvengatam, was killed in the early hours of Sunday, July 14 near Madhavaram in Chennai. Police claim that Thiruvengatam had attacked them and tried to flee when they opened fire on him. 

Police sources also say that Thiruvengatam had admitted to supplying the weapons used to murder Armstrong who was hacked to death on July 5. At around 5:30 am, Thiruvengatam was taken to a shed where he allegedly told police had hidden the weapons. Further, according to police sources, Thiruvengatam had also admitted to supplying the country-made bombs that were seized from the suspects. He was the first to attack Armstrong the day he was murdered, police add. Thiruvengatam was a history-sheeter who was, according to reports, already involved in three other murders. 

Thiruvengatam along with 10 others have been in police custody since July 11 by order of The Chief Metropolitan Magistrate Court in Egmore. V Ponnai Balu (prime accused), K Manivannan, Thiruvengatam, D Ramu, J Santhosh, S Thirumalai, G Arul, D Selvaraj had surrendered soon after the murder. Three others, Gokul, Vijay and Sivasakthi who were arrested later. 

Armstrong was brutally hacked to death on July 5 outside his Perambur home in north Chennai. A well-known Buddhist Ambedkarite and a popular leader in his own neighbourhood, his murder led to criticism of the Chennai police for the deteriorating law and order situation.