Special Commissioner of Police (Crime) Taj Hassan confirmed the development and said the Crime Branch has initiated inquest proceedings in the case.
The 70-year-old ex-serviceman from Haryana's Bhiwani district consumed poison in the lawns behind Jawahar Bhavan, which houses some offices of the Ministry of External Affairs, on November 1. He was rushed to RML Hospital where he died later.
Grewal's suicide had yesterday snowballed into a huge political showdown in the capital with Congress Vice President Rahul Gandhi being detained twice by Delhi Police amid high drama and Chief Minister Arvind Kejriwal also being detained by the policemen.
Grewal, along with three of his companions, had come to the city apparently to submit a memorandum to the Defence Ministry over the issue of OROP.