Watching The Defendant

Reporter as cameraman: Mr. Wilson showed no reaction. A glaze cast across his eyes and remained as his erstwhile friends ascended the witness stand one by one to identify him. They said he was the man who took a .44-caliber revolver, met with the undercover detectives in a car on the pretense of selling them a gun and fired one bullet through the back of each man's head.

On the second day of testimony, prosecutors called Jessie Jacobus, a 6-foot-3, 320-pound man who has admitted to riding with Mr. Wilson during the shooting, and asked him to decipher an audio surveillance recording. As the sounds of the detectives' last conversations resounded, their families wailed and collapsed and…