The body had bullet wounds, they said.
Police is investigating whether she shot herself or there was any foul play in the incident as no suicide note was recovered from the 22-year-old deceased identified as Siuli Batra, who hailed from 24-Paragnas in West Bengal.
A senior police official said the incident came to light at around 4 am when a woman constable went to relieve Batra from her duty at the watch tower of 88-Battalion in Dwarka Sector 8.
Siuli was found dead with bullet wounds in her stomach, the official said, adding that she was carrying her SLR (Self Loading Rifle). Batra is unmarried.
She was originally posted with 135 Battalion of CRPF based in west Delhi's Vikaspuri. However, she was moved to the 88-Battalion where she was assigned to be on duty from 2 am to 4 am on the watch tower.
"Nobody knows when the incident took place. It must have happened in between 2 am and 4 am when she was on duty. The woman constable who came to relieve her found her lying in a pool of blood," the official said.
A case has been registered and further investigations are on, police said.
