SAN DIEGO -- A gunman robbed an adult book store overnight in Kearny Mesa, police said.

Shortly after midnight, a man pretended to shop for several minutes at the Adult Emporium, 5101 Convoy St., and then jumped over the counter , San Diego police Officer Brad Ruff said.

The robber demanded cash from a female clerk at gunpoint, Ruff said, adding that the clerk complied and the gunman ran off southbound on Convoy Street.

A witness reportedly saw him get into a silver Ford Explorer.

Police described him as black and in his 20s, with a stocky build. He was last seen wearing a blue ball cap, black fur-lined hooded jacket, black pants, white shoes and black-rimmed glasses, Ruff said.