Eddie Morant, a 21-year-old Northwest Washington maintenance man, knew the rape victim was wrong the instant she pointed out her alleged rapist to police.

Morant knew it beyond question, because the man she picked out of the police lineup was he -- and he knew he didn't do it.

For Morant, however, knowing he was mistakenly accused was only the beginning of his criminal justice nightmare. Over the next 11 months he would spend time in jail, be indicted as a rapist and come perilously close to standing trial.

In the end, probably only an assistant U.S. attorney troubled by inconsistencies in the evidence saved Morant from possibly going to prison for a crime he never committed.

The case of Eddie Morant, unsettling though it may be, is not unique. In the last two years, at least two other Washington residents have found themselves indicted -- and in one case convicted -- for crimes they did not commit.

In one instance, William H. Buie, a tree trimmer who lived on 12th Street NW, mistakenly was arrested by police officers searching for a murder suspect. He was "positively" identified by two eyewitnesses and indicted for murder before the real culprit was discovered.

In another case, a Southwest Washington teen-ager was arrested, tried and convicted for the street robbery of an elderly woman. Two days after his conviction, city prosecutors discovered that another individual had previously confessed to the crime.

Without exception, the experiences were personal torments -- to themselves as well as friends and families. Two of those wrongly accused now live with the knowledge that, save for the fortuitous intervention of prosecutors and police -- and a large measure of luck -- they probably would have gone to prison.

"The thing that really hurt me about it was that I was actually locked up in front of my girlfriend and daughter for something I hadn't done," Buie recalled. "And then it got so some people thought I did it . . . . I would be thinking to myself, 'Am I going to get locked up and face 20-years-to-life for a crime that I never committed?' "

The mother of the Southwest youth who was wrongly convicted felt the same anguish. "It was an awful thing to happen to a 15-year-old boy," she said. "I could have screamed murder but there was nothing I could do."

Prosecutors are sympathetic to the suffering such mistakes cause, according to U.S. Attorney Charles F.C. Ruff. "Everybody in the business views it as the ultimate nightmare to wake up one day and discover you have convicted the wrong person," he said. "The most difficult cases to try and . . . investigate are those with a victim who is the sole source of the identification. You try to prove the negative, and you try to track down all possible corroborating evidence.

"But sometimes the identification is strong, and the case rests on that to go to trial," he said.

Ruff and other prosecutors maintain that such instances are extremely rare. They say they drop 20 percent of all felony arrests brought in by police officers for lack of evidence, misidentification or other reasons. Another one-third are dismissed before indictment.

But there are also exceptions, the most famous of which occurred in 1974 when Bradford G. Brown of Northeast Washington was wrongly convicted of murder and served five years in prison before police learned that another man had committed the crime.

"It's the most frightening part of the criminal justice system, the specter of innocent people being convicted of crimes they did not commit. I think it happens more than people realize," says Washington defense attorney Timothy Junkin.

Morant's saga began last December at D.C. police headquarters when a woman, sorting through photographs of men fitting the description of someone who had raped her outside her Northeast home, picked out Morant's picture -- still in police files after a burglary conviction several years before. The woman's identification was enough for police to arrange several weeks later for Morant to appear in a police lineup, when he was again identified as the rapist.

Initially, the U.S. attorney's office flagged the case as needing further investigation. Morant, for example, was only 21 years old and the victim had said the rapist had told her he was 23. There was also the rapist's assertion that he had just been released from Lorton Reformatory, but there was no record of Morant having served at Lorton recently.

Morant had also maintained he was with his girlfriend at the time, but his alibi was weakened when his girlfriend told police she could not remember whether he had been with her when the rape occurred. That, coupled with the victim's certainty that Morant was the man, proved enough for prosecutors.

In July, a grand jury indicted Morant for armed rape and sodomy.

"The victim saw the guy for a long time, and her description was very good," said Morant's attorney, Stephanie Duncan-Peters. "It matched Eddie. I was very worried that he would lose it, and I didn't think he had done it."

Assistant U.S. Attorney Brooks Harrington, who was assigned to try the case, was curious about some of the case's inconsistencies.

On a hunch, he contacted Lorton officials and requested a more complete list of all prisoners released during the months prior to the rape. His request was rejected as impractical. He turned to a confidential source who leaked him the daily manifests of the prison bus, which included the names of every prisoner who was transported to and from the facility for the two-month period prior to the date of the crime.

After culling through thousands of names for prisoners who actually had been released, Harrington narrowed his list to about 600. Then he used a sophisticated law enforcement computer system to determine the criminal record and physical description of each prisoner on his list.

In particular, he looked for individuals with prior sex offenses who lived in the victim's neighborhood and whose height, weight and age characteristics matched those the victim originally had provided. After two weeks of continuous investigation, Harrington coaxed out of the computer seven new names.

One attracted his attention -- that of a 23-year-old man who lived near the victim, who had been released from Lorton in October and had since been convicted of two other rapes during the same time period.

Harrington went to D.C. police headquarters where he pulled photographs of each possible suspect. He made a stunning discovery; the picture of the 23-year-old man showed him to be a dead ringer for Morant.

On Nov. 2, the day Morant was scheduled for trial, the U.S. attorney's office dismissed the rape charge and is now determining whether to bring charges against the look alike.

"I knew they had the wrong one when they had me," Morant said after the charges against him were disimssed. "If they found me guilty -- that's life, or 20 years. Man -- I couldn't do that time . . . . They'd have to go ahead and shoot me."

Morant became entangled in the criminal justice system because -- with his prior arrest -- his photo was on file with the police department. William Buie, who was mistakenly indicted for murder in August 1980, became entangled with police but in a different way.

On July 14, 1980, Buie, 22, stepped off a Metrobus near 14th and U streets NW on his way home from work. He waved to a friend standing on a nearby porch, said hello to another tinkering with his car, tossed horseshoes with a third.

Several blocks away on another Metrobus, a man was fatally shot and, as passengers ducked for cover, the gunman fled. Police recovered only a spent slug. A description was broadcast, and within 20 minutes, Buie was stopped and taken to the scene. Two passengers identified him as the gunman.

"I thought they were crazy when they said I shot somebody on a bus," Buie recalled. "I knew where I had been . . . . The next thing I saw was the lady nodding her head, saying, 'Yes, that's the one.' "

Buie and his attorney, James S. Kunen, interviewed the witnesses who had seen Buie walking home, but it was not sufficient to convince the grand jury or prosecutors, who asserted in court papers that the government's eyewitnesses "were positive."

Enter police detective Robert J. Kanjian, a 16-year veteran, who had won national praise in 1979 for disproving the charges against Bradford Brown after Brown had served five years for a murder he had not committed.

Kanjian knew nothing of the Buie case when he learned early this year that a recently arrested robbery suspect was willing to offer information about a homicide on a bus in exchange for a good plea bargain in his own case. Kanjian checked with Metro officials and found that only one bus murder had occurred in 1980. Kanjian went to the file and saw that someone -- Buie -- had already been charged in the case and was scheduled for trial.

"Oh my God," Kanjian recalls thinking. "This is Bradford Brown all over again."

He went to assistant U.S. Attorney John J. McDermott, who arranged the plea bargain with the man, who in turn said a friend -- "B.J." -- had once talked of killing a man on a Metrobus. The man said the gun involved was already in police possession, and he gave them the gun owner's name.

Kanjian searched through police property records for a gun that matched the description the man had given him during the interview. He discovered the report of a white-handled, five-shot revolver that had never been linked to an owner. Using ballistics tests, he compared the gun and the slug recovered in connection with the Metrobus murder. It was a perfect match.

Then McDermott and Kanjian summoned the gun's owner. He told them that "B.J." had borrowed his gun one day in July and returned it with one less bullet. "B.J." also had shown him a newspaper account of the Metrobus murder and Buie's arrest and boasted that police had the wrong man.

With this information, McDermott arranged for the case against Buie to be dismissed. At the same time, police began a search for "B.J."

The man called "B.J." recently was killed in an unrelated incident.

Though Buie and Morant were proven innocent before their cases went to trial, the Southwest teen-ager arrested last year was not so fortunate.

The youth was picked up by police in the 1300 block of Canal Street SW because he matched the description of the person who had just robbed an elderly woman nearby. When he was positively -- but mistakenly -- identified as the robber by a witness at the scene, he was charged and imprisoned for two weeks before he was released to his mother's custody.

On Sept. 15, the youth was tried and convicted by a Superior Court judge and sent to a juvenile institution pending sentencing.

Two days later, the Corporation Counsel's office, which has declined comment on the case, called in the youth's attorney. She was informed that someone else had confessed to the robbery -- before the youth's trial -- but that police had not informed the officer and prosecutor handling the case.

The judge promptly threw out the conviction.

"Don't be bitter," the boy's defense attorney quoted the judge as saying at the time. She said the judge added that "even though you were found guilty, you were convicted under one of the best systems that we know of."