If there is one thing about which prosecutors and defense attorneys agree, it is that single-witness identification cases are trouble. They are trouble because often the only thing the prosecution has to prove its case is the word of the victim against the word of the defendant.

"I think if you look at some of the cases where the jury acquits a defendant , you'll find they involve that kind of difficult identification," said U.S. Attorney Charles F.C. Ruff. " . . . Every prosecutor will tell you that those situations are the most difficult to cope with."

Defense attorneys see it somewhat differently. They believe that when a victim's word is pitted against a defendant's, jurors are more likely to believe the victim. They cite evidence compiled by Seattle psychology professor Elizabeth F. Loftus, who was hired last year by the D.C. Public Defender's Office to survey Washington-area jurors.

She found that many jurors believe that extreme stress and fright experienced by crime victims enhance their ability to remember, causing a mental fixation best captured in the statement: "I'll never forget that face."

Loftus, however, claims her own research shows that one's ability to remember is actually reduced during a criminal attack.

A defense lawyer cited "a gnawing feeling" that an innocent person could be convicted and imprisoned but prosecutors said half the 6,000 felony cases investigated here are dismissed before indictment in a winnowing process that effectively prevents mistakes.