GARLAND, Texas (CBSDFW.COM) – A man suspected of trying to rob another man and his girlfriend during a transaction that began on line, was shot and killed outside a Garland home.

It happened Sunday, September 9, just after 10:30 p.m. in the 3700 block of Hawaii Drive.

Garland Police said when officers responded to a shooting call, they found an unidentified man shot in the front yard where Quan Tran and his girlfriend had been waiting.

Police believe the unidentified man showed up at the home to rob Tran, 23,  and his girlfriend.

Detectives said Tran and his girlfriend were in front of the home waiting to purchase a camera that was being sold online by someone they did not know.

While they were outside, the man approached them with a gun demanding money. Police said he “began assaulting Tran, threatening to shoot him and his girlfriend. Tran produced a handgun and shot the robbery suspect.”

This is an ongoing investigation. No criminal charges have been filed at this point.