IN AMERICA / By BOB HERBERT

A little before 12:30 p.m. on Dec. 30, 1997, a masked gunman walked into a bodega on Strauss Street in the Brownsville section of Brooklyn. There were four other people in the store: the owner, Jesus Martinez, known affectionately in the neighborhood as "Poppy," a teenage employee named Frankie Rodriguez, and two young customers, Candace Daniel, 13, and Steven Green, 15. 

The gunman raised his .38-caliber revolver and shot Mr. Martinez in the chest, killing him. Frankie Rodriguez turned and ran. The gunman chased him down an aisle, shooting at him. When Mr. Rodriguez stumbled and fell, the gunman stood over him and fired a fatal shot into his back. 

Candace Daniel ran out of the store and was not hurt. Steven Green, who had been playing a video game near the rear of the store, hid in a back room until the gunman left. He was not injured either. 

The police described the crime as a botched holdup. 

A little over a week later, on Jan. 8, 1998, cops arrested a 27-year-old rapper and songwriter named Antowine Butts. The office of the Brooklyn district attorney, Charles Hynes, then went to work putting together a first-degree murder case against Mr. Butts. This was not easy because Mr. Butts was innocent. But Mr. Hynes's office has shown on several occasions that innocence is no impediment to prosecution. 

Jay Salpeter, a private investigator and former New York City detective who did investigative work for the defense, told me, "This was a really bad one. The guy was totally innocent. He was home with his three kids." 

The police and the district attorney's office used smoke, mirrors and two of the world's worst witnesses to try to convict Mr. Butts. Both witnesses picked him out of a lineup. One of the witnesses was a self-confessed crackhead who all but implicated himself in the crime. The other was a terminally confused young woman who said she had just happened to be passing by when the murders occurred, saw Mr. Butts and decided, on the spot, to accompany one or two other men who she said were involved. 

To read the transcript of the trial of Mr. Butts (who once was caught jumping a turnstile, his only previous brush with the law) is to immerse oneself in the frightening reality of a criminal justice system gone haywire -- a system that simply closed its eyes to the most elementary aspects of truth and falsity, guilt and innocence. 

The key witness against Mr. Butts was a criminal with a long record named Martin Mitchell. Mr. Mitchell told investigators that he -- Martin Mitchell -- had been at a meeting at which the murder of Mr. Martinez was planned. And 
Mr. Mitchell was outside the bodega the next day when Mr. Martinez and Mr. Rodriguez were killed. Did it occur to the police and the prosecutors that maybe Mr. Mitchell was involved in the crime? 

Apparently not. He wasn't charged with anything. 

A top aide to Mr. Hynes told me: "You can be at a meeting where an event is planned and not be a member of the conspiracy." 

So the police and the D.A.'s office took Mr. Mitchell at his word when he said he was not involved in the crime, and they believed him when he said that Mr. Butts was. If you want a sense of how worthless Mr. Mitchell's testimony was, just consider that he admitted on the witness stand that in the 12 to 24 hours leading up to the crime he had been smashed out of his mind on crack cocaine, marijuana and alcohol. 

"My mind wasn't there," he said when he was asked why he never notified the police or warned anybody in the store that a murder was planned. He said, "My mind was just about getting high." 

When he was asked what time the shooting took place, he replied: "I can't remember people. How am I going to remember time?" 

Mr. Butts should never have been tried, but he was. Two weeks ago a jury, after only a brief deliberation, acquitted him. But by then he had already spent two years in jail. That's two years lost from a young man's life because of the incompetence -- or worse -- of the police who investigated this case, and Mr. Hynes's office, which prosecuted it. 

And the real killer is still at large.