A 20-year-old Columbia woman was stabbed to death yesterday during a possible robbery at the High's store in Columbia where she worked as a clerk, Howard County police reported.

Angelica Velazco of Twin Rivers Road in the Wilde Lake area was stabbed about 1 p.m. in the convenience store in the Wilde Lake Village Green shopping center, police said.

They said a customer, whom they did not identify, found the body when he entered the store.

Police said that they want to question a man they described as in his late teens, about 5 feet 11, with what they said was an average build and sandy blond, collar-length hair. They said he was wearing a green T-shirt and a blue jean jacket.

It could not be learned immediately whether anything was taken from the store or whether a weapon was found.

A friend of the slain woman said he understood that she had been alone in the store at the time of the stabbing. A person familiar with the store said that it is in a cluster of stores but located in such a way that people driving past cannot see inside.

An employe of another High's in Howard County described Velazco as friendly and popular.

A friend of the family said that Velazco lived with her mother a few blocks from the store. He said he believed that the Wilde Lake High School graduate had worked at the store for about a year and a half.

She had recently completed a course in hairdressing and was about to leave the High's job to work as a hairdresser, the friend said.

The friend, who did not wish to be identified by name, called the killing "one of those things that's just incredible . . . . "