NASHVILLE, Tenn. -- Police are searching for armed robbers who killed two Madison convenience store clerks Tuesday around 9:30 p.m.

IMAGES: 2 Killed In Market Robbery

Metro police spokesman Don Aaron said the two robbers demanded money, but became frustrated when the clerks at AMPM Discount Tobacco began speaking in Arabic and opened fire.

The Egyptian clerks and have been identified as Salama Estfanos, 23, and Bishouy Hanna, 24.

A customer, James Lee Rayburn, 55, of La Vergne was also in the store and wounded by the gunfire. A second customer, Dale Smith, was unharmed.

Rayburn was in critical condition at Vanderbilt Medical Center as of 4:40 p.m. Wednesday.

Video from the market security cameras shows two men walking into the store late Tuesday night, one pulling a pistol, the other carrying a shotgun.

The gunmen ordered the two clerks onto the floor.

Friends and family members told Channel 4 that both of the slain victims were very friendly, happy people.

The clerks were not related but came to America together after winning a lottery for visas to travel to the U.S.

Estfanos, or "Sam", as his friends called him was sending money back to Egypt to pay for a big wedding for himself and his fiancé.

Hanna's cousin said he never worried about working in a convenience store because he knew to hand over money if trouble walked in.

Police have not identified the robbers, whose faces were covered by masks, but say they might have left the market in a sport utility vehicle.