Usman, who earlier worked as a delivery executive, was released after he was questioned. He admitted Vishal had shot himself and led the police to the weapon.
Even as several investigators were looking for the accused in the it was one of the alleged conspirators who was earlier found at who led the police to other accused.
Seven people have been arrested in connection with the gunpoint robbery of a delivery agent and his associate inside the Pragati Maidan tunnel here, police said on Tuesday.
The individuals, namely Manoj, Ravi, Rahul, Sonu, and Deepak, have confessed their involvement and now face charges of robbery, criminal conspiracy, and possession of illegal weapons.