A Bronx man allegedly helped his buddy shoot a gas-station attendant in Queens — and then looted the joint of cigarettes and cigars as the victim lay dying on the ground, authorities said today.

Christopher Roberts, 21, was arrested today for the July 25 murder of Nadeem Khan, a 39-year-old Pakistani immigrant working the graveyard shift at the Mobil station on Roosevelt Avenue near College Point Boulevard.

Roberts told cops that he and alleged accomplice Maurice Echols, 21, of Jamaica, Queens, entered the gas station at 1:20 a.m. officials said. A surveillance camera then caught the fatal shooting on tape, authorities said.

In a statement to police, Roberts said Echols was the one who shot Khan, sources said. While Khan lay dying on the floor, the two robbers then took their time looting cigarettes and cigars from behind the register before fleeing, sources said.

Echols, who has not been charged in this case, is currently being held on $400,000 bail for allegedly robbing a Chinese restaurant with Roberts a few days later, according to the DA press release announcing Roberts’ slay bust.

Roberts, who was charged with murder and robbery, is being held without bail, said a spokesman for DA Richard Brown.