Sandeep Bhardwaj was the owner of a marble dealership.
An Aam Aadmi Party leader was found dead at his residence in west Delhi's Rajouri Garden on Thursday, police said.
The BJP demanded a thorough investigation into the matter even as Delhi Chief Minister Arvind Kejriwal condoled his death.
The body of the man, identified as 55-year-old Sandeep Bhardwaj, was found hanging at his residence, they said.
The police received information from the Kukreja Hospital that Bhardwaj, a resident of Rajouri Garden, was brought dead from his residence, Deputy Commissioner of Police (West) Ghanshyam Bansal said.
The crime team was called to the spot. The man was the owner of Bhardwaj Marbles and was a divorcee who lived with his two daughters and a son, police added.
Delhi BJP spokesperson Praveen Shankar Kapoor said the report of Bhardwaj's sudden suicide has shocked the people of Delhi, especially those from the Moti Nagar Assembly area.
"People of Delhi want to know why a person, who till few days was actively doing political work apart from his business, has suddenly committed suicide and therefore the police should conduct a thorough investigation to bring out the cause of the suicide," he said.
Mr Kejriwal said the entire party was standing with his relatives at this time.
"Extremely saddened about the untimely demise of AAP worker Sandeep Bhardwaj. May God give peace to his soul. In this hour of grief, our condolences are with them and the entire party is standing with his relatives," he said in a tweet in Hindi.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)