A brazen conversationalist whose stories often end with a sharp point--of a knife, that is--is suspected of robbing 12 cabdrivers in the District since Jan. 10, D.C. police say.

Robbery Squad Sgt. Edward Dory said the man, in his 20s, who sports a goatee and slight mustache and usually wears a sports coat and blue jeans, has made a practice of hailing cabs at some of the city's better addresses or even calling a cab to pick him up.

He always has an engaging story to tell during the ride to his destination, police say. On a trip from Arena Stage on June 11, the man discussed the play.

Last Thursday, after calling for a cab to come to Columbia Hospital, the man told the driver how his wife has just had a baby at the hospital and even presented what he said was a photo of the child, police said.

In both cases, as in the other similar robberies, when he reached his destination, the man drew a knife and took the drivers' money. No serious injuries have been reported in any of the incidents.

Police said the man generally hails cabs at different locations, and the times of the robberies have varied from early afternoon to late at night.

A $1,000 reward is being offered for information leading to the man's arrest and conviction, police said yesterday.