For the second time in six weeks, a skinless human arm was found in Prince William County yesterday, this time in a drainage ditch near Dale Boulevard.

Police believe the arm, found by a man cleaning the ditch near Danbury Court, belongs to the same body as an arm found Dec. 26 propped against the door of a Woodbridge restaurant.

Dave Watson, the investigator assigned to the earlier case, said the discovery was "no less disgusting than the first time."

The right arm found yesterday appeared to be from a white man, Watson said, and had been removed in textbook surgical fashion, as was the first arm.

"I would venture to say that it likely came from the same body," he said.

Authorities believe the two arms were stolen from a laboratory or medical school because of the precision with which they were removed and the fact they were bloodless and smelling of formaldehyde.

Watson said the latest discovery had yielded fingerprints -- as did the first arm -- and "other promising evidence that will pinpoint where it came from."

The two discoveries were made less than 10 miles apart.

"I thought the first discovery was an isolated incident," he said. "The first time I think it was a prank. I think this was a deliberate attempt to get rid of the evidence."