The Post-Dispatch reported that the man had his handgun in a pocket when the robbery suspects came in and demanded his pickup truck, which was parked outside. Both men fell near the pickup after being shot.
The homeowner's gun, as well as weapons linked to the two suspects, were found at the scene. The gun found with Warren had been reported stolen Sunday in Florissant, the Post-Dispatch reported.
Neighbors told the newspaper that the homeowner, a retired fireman, is a friendly man who never hesitates to say hello or help a neighbor in need.
"The man takes his snow blower and clears my porch," Peggy Armbruster said. "He takes care of a neighbor who is blind. He likes to tinker in his garage, and he is back there a lot."
Armbruster said she did not know her neighbor carried a gun, but that he had been a robbery victim in the past.
No charges have been filed against the man.