An independent investigator says he found nothing criminal about Mayor David Dinkins' transfer of stock to his son, but he has a doubt about the mayor's testimony on the matter.

"We have not cleared him," Elkan Abramowitz, a former assistant U.S. attorney, said Thursday. "We have simply concluded the evidence is legally insufficient to warrant a criminal prosecution.""As far as I'm concerned, I've been cleared and that's the end of it," Dinkins said. "I don't think there is a cloud hanging over me."

Abramowitz said at a news conference that efforts to authenticate the date of a crucial document - a handwritten letter about the stocks from Dinkins' son, David Dinkins Jr. - were inconclusive. He said that was in part because the younger Dinkins, who lives in Las Vegas, Nev., refused to come to New York to testify.

A Secret Service laboratory analysis of the ink, paper and indentations on the letter "casts doubt in a troubling way on the testimony by the mayor and his son," said Abramowitz, who conducted the probe for the city Department of Investigation.

The mayor and his son testified when the stock transfer was the subject of an earlier investigation by the U.S. attorney's office. That probe also found no evidence of wrongdoing.

In the letter, which begins "Dear Dad," David Dinkins Jr. agreed to pay his father $58,000, with interest, for 588 shares of stock in the Inner City Broadcasting Co., which has an interest in a cable television franchise.