A CISF constable allegedly killed himself using his service rifle at the Nangloi Metro Station on Thursday, officials said.
The incident took place around 7 am. The body of the deceased jawan, Shahre Kishore, was recovered from near the X-ray baggage scanner, they said.
The constable is said to have joined the Central Industrial Security Force (CISF) in 2014.
Preliminary investigation suggests that the jawan, deployed in the CISF unit that guards the Delhi Metro, killed himself using his service weapon, they said.
An inquiry is being undertaken by the paramilitary force apart from the Delhi Police, the officials said.