A 31-year-old man has been sentenced to four life prison terms for executing a federal witness who fingered a dozen suspected drug dealers in South Baltimore's Westport neighborhood. The victim, Kareem Guest, pleaded for mercy before being shot a dozen times on the street in 2009.

Guest was outed as an informant after an FBI report detailing his cooperation was leaked and posted throughout the neighborhood, where Guest and his killer lived. The shooter, Antonio "Mack" Hall, 30, was found guilty by a jury in U.S. District Court in Baltimore in August.

The Sun's court reporter, Tricia Bishop, recounts the chilling details of the case in her coverage of the trial. Testimony revealed that Hall had a history of retaliating against witnesses and so-called "snitches," and was linked to the killing of a teen-aged drug dealer, shot as he played video games, and to the shooting of a junkie who had helped police arrest one of his friends.

Guest, arrested on heroin distribution charges in 2008, had agreed to cooperate with the FBI to bring down a gang selling heroin branded "Dynasty." His help led to the convictions of eight defendants, including the ring-leader who went away for 22 years.

A defense attorney for one of those suspects was given a copy of Guest's FBI statement so he could prepare his defense. Defense attorneys are allowed to share the information with their clients, but not hand over hard copies. The attorney admitted to giving a copy to his client and to his client's mother.

Once on the street, the document became a virtual wanted poster, prosecutors said, leading to the killing of Guest. The attorney, a former federal prosecutor from Detroit, was not prosecuted, but he was later disbarred for taking on clients and pocketing fees without telling his own law firm.

Lawyers for Hall argued that Guest had many enemies and that their client was the killer, but the jury rejected the arguments. The case highlighted the troubling issue of witness intimidation and showed how dangerous it is to be an informant.

Guest's statement to the FBI was tacked to telephone poles and to a basketball hoop in Westport and a copy was even found in a jail cell in New Jersey.