WALNUT CREEK -- An employee at a farmers market escaped physical injury Monday night but lost an undisclosed amount of money when he was robbed in the parking lot by a person with a knife, police said.

Police dogs were unable to locate a man suspected in the robbery, which occurred about 11:04 p.m. at 1510 Geary Road, the location of a Sprouts Farmers Market, according to a news release from Walnut Creek police Sgt. Mike Sugrue.

The employee was outside the store when the suspect approached him, held out a knife and demanded money, Sugrue said. The employee gave over his money, and the suspect fled on foot. Police did not say in which direction he went.

The suspect was described as a white man in his early 20s, approximately 5 feet, 10 inches tall, a sunken-in face, short hair and pale skin, Sugrue said. He was wearing a black hooded sweatshirt, black pants and tan-soled shoes, Sugrue said.

Anyone with information is asked to call Walnut Creek police at 925-943-5844.

Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rdERH.