A personnel of Defence Security Corps (DSC) was killed at the Heavy Vehicles Factory at suburban Avadi on Friday after his colleague opened fire, Defence sources said.
DSC personnel are posted on security duty at the gates of defence establishments.
The incident happened in the early hours on Friday when Nilambar Sinha, posted here three days ago, opened "random fire" at a place meant for jawans to take rest, killing Garjesh Kumar on the spot, they said.
Sinha later come out and was making some "threatening remarks" at others but was subsequently persuaded by senior DSC officals to surrender.
He would be subjected to an internal probe, even as a Court of Inquiry (CoI) has been ordered into the incident, they said.
The reason for Sinha killing his colleague was yet to be ascertained and a probe was on, they added.
The body of Kumar, a native of Himachal Pradesh, was later shifted to a government hospital for postmortem.
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