(CNN) -- Photographs of a "person of interest" in the case of slain college student Eve Carson show him possibly using her ATM card, said Chief Brian Curran of the Chapel Hill, North Carolina, police on Saturday.
"This is our biggest break so far in the case. I know we're still in just the first couple of days in this, but this is our strongest lead right now," Curran said. "We're hopeful that we'll be able to get this guy identified."
The photographs were taken by an ATM camera in the Chapel Hill area as the person appeared to be using one of Carson's ATM cards and might have been driving her car, Curran said.
He would not say when the photographs were taken.
They show a young man wearing a hooded sweatshirt and a baseball cap, but police do not know his identity, Curran said.
Police were also releasing a photograph of the cap the man was wearing.
Carson, a University of North Carolina senior and student body president, was last seen about 1:30 a.m. Wednesday by her roommates, who were leaving their living quarters and invited her along. Carson was studying and declined, saying she had work to do, Curran said.
She was found shot to death in a suburban neighborhood not far from campus about 5 a.m. Wednesday. Watch police describe finding the body »
Her car was found in a neighborhood to the west, about a block or two from where she lived, Curran said Friday.
"It feels like a random crime," he said Saturday.
The medical examiner told police that there were no other injuries to Carson's body besides the gunshot wounds and no signs of sexual assault, he said.
Carson, 22, was a pre-med student who had a double major in political science and biology.
She was a recipient of the university's prestigious Morehead Scholarship and a member of the Phi Beta Kappa honor society, the university has said. E-mail to a friend