Thiruvengadam was one of the suspects arrested for K Armstrong's murder.
One of the accused involved in the murder of the Tamil Nadu BSP Chief was killed in an encounter with the police in Chennai late last evening, officials have said.
Police sources said Thiruvengadam was taken to the spot to recover weapons used in the killing of K Armstrong when he fired at the police officials with the recovered gun.
He was injured in the retaliatory firing and rushed to the hospital. "He was declared brought dead by the doctors," officials said.
K Armstrong was hacked to death by six bike-borne men near his house in Chennai earlier this month.
The six men attacked Armstrong when he was having a discussion with a few party functionaries near his house in the city's Sembium area and then fled. The family rushed him to a hospital, but he was declared brought dead.
Thiruvengadam was one of the suspects arrested allegedly for K Armstrong's murder.
A lawyer, Armstrong was elected to the Chennai Corporation Council in 2006. He shot to fame after he organised a mega rally in Chennai two years ago and invited BSP chief Mayawati.
BSP chief Mayawati has demanded a CBI investigation into the attack. "I urge the state government, especially the Chief Minister, to ensure law and order in the state. The weaker sections, in particular, should feel safe. Had the government been serious, the accused would have been arrested. Since that is not the case, we urge the state government to refer the case to the CBI," she had said.