Suraj, 28, and Anil, 22, were arrested from Ranhola in connection with the robbery in the area on October 21, Deputy Commissioner of Police M N Tiwari said.
Suraj holds a diploma in computer engineering and had won two gold medals in national-level taekwondo championships. He had also participated in popular television show 'Indian Idol' as a singer, Tiwari said.
Suraj had been arrested twice previously.
"He was arrested in a case lodged at the Janakpuri police station in 2014 and a number of mobiles were recovered from him. He was again arrested in June, 2017 in a robbery case registered at the Tilak Nagar police station," the officer said.
In the October 21 incident, the accused had robbed four men at gun-point. They fled with a gold chain and the wallet of the complainant, Deepak.
The wallet, a country-made pistol, a live cartridge, a pepper spray and a two-wheeler used in the robbery have been recovered. Suraj was involved in 24 cases of robbery and theft, the DCP added.