Police Chief Brian Curran would not say where the two ATMs were located, but he did confirm that investigators found Carson's cell phone last week in a shopping center near U.S. 15-501 about 1.5 miles from downtown Chapel Hill.

That area includes University Mall, Ram's Plaza and Eastgate Shopping Center, along with several banks that have drive-through ATMs. Such ATMs are rare in Chapel Hill because of strict land-use regulations. Curran would not say exactly where the cell phone was found.

The man in convenience-store photos released Monday evening is not wearing the same vintage Houston Astros ball cap as the man in the ATM photos released Saturday morning.

Both photos depict a young man with long hair. In the ATM photo, it sticks out from a hooded sweatshirt or jacket. In the convenience store photo, it appears to be tied back.

"To my eye, it appears to be the same person," Curran said.

Investigators have received more than 200 calls from tipsters, most of them since police released the bank surveillance photos.

"Prior to the release of the photos, the tips were kind of trickling in," Curran said.

After analyzing the bank photos more closely over the weekend, Chapel Hill police said they think there is a second man in the back seat of the vehicle in the photo. They think the vehicle is Carson's blue 2005 Toyota Highlander and have contacted Toyota representatives to make sure.

"I still can't tell you 100 percent, but it appears to be a Toyota Highlander," he said.

Curran said he can't identify the second person seen in several stop-action photos. The pictures are not clear enough, he said.

"I've seen basically a silhouette of a guy in the back seat," Curran said. "If we could see this guy's face, we'd have that out there."

The body of Carson, 22, was found in the Hillcrest neighborhood northeast of campus about 5:15 a.m. Wednesday with gunshot wounds, one to the head. A memorial service was held Sunday in her hometown of Athens, Ga.