Bhoomappa, 29, who hailed from Karnataka, shot himself around 3.25 p.m. Police have not recovered any suicide note.
"He shot himself in the head using his INSAS rifle. He died on the spot," a senior police official said.
He was on sentry duty at the 8, Akbar Road official residence of Sinha when the shooting took place, said a police official.
"We got a call around 3.30 p.m. and rushed to the spot. We found a man lying in a pool of blood. He was rushed to the Armed Forces Clinic where doctors declared him dead," said Tughlaq Road police station chief Madan Gopal.
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