"We have not said that we linked the two cases, but we're just saying that we're working cooperatively on them," said Raleigh police spokesman Jim Sughrue.
The first case took place in May. Samuel Haj-Hussein worked at the In and Out Food Mart and was found shot to death inside. Three weeks later, a restaurant employee found Leroy Jernigan shot and killed inside the Circus Restaurant.
Haj-Hussein's minivan and Jernigan's truck were both missing from the crime scene. Police said they were each dumped within a block of each other in West Raleigh. Now, authorities have gone door-to-door to about 1,000 homes in the area.
"People might have a piece of information that might not seem significant, but could turn out to be helpful to the investigations," Sughrue said.
Mark Newton hadn't even heard about the murders until investigators came knocking on his door.
"That someone around here may have been involved in something like that or people getting around the neighborhood might be involved in murders -- yeah (it) puts you a little bit on edge," Newton said.
Police said two men were seen in and around Jernigan's red Dodge pickup after the crime. Their composite pictures are on the calling card investigators are leaving.
Anyone with information about either is asked to call a special hotline set up for the two cases: