A federal jury in Brooklyn is expected today to begin weighing the capital charges against the man accused of executing two undercover detectives on Staten Island in 2003.

If the jurors convict Ronell Wilson, 24, of the most serious racketeering charges he faces, they will return to the federal courthouse at Cadman Plaza in January to decide whether to sentence him to death. The two detectives, Rodney Andrews, 34, and James Nemorin, 36, were killed during a meeting with Mr. Wilson and a second man to purchase a handgun as part of a sting operation.

Although several men were involved in making plans to rob the detectives, it was Mr. Wilson alone who decided to execute them, an assistant U.S. attorney, Morris Fodeman, said during closing arguments yesterday. The motives for the shootings included Mr. Wilson’s greed for the money the detectives carried and a desire for notoriety, Mr. Fodeman said.

“Why did he execute two men in cold blood?” Mr. Fodeman asked. “The answer is because he could. He wanted his cut of $1,200, and he wanted to impress his criminal friends.”

Mr. Fodeman concluded by quoting from violent rap lyrics discovered on Mr. Wilson at the time of his arrest.

“I won’t stop until I’m dead,” Mr. Fodeman said Mr. Wilson had written.

An attorney for Mr. Wilson, Ephraim Savitt, assailed the credibility of the one eyewitness to the murders, an accomplice of Mr. Wilson’s who has pleaded guilty to second-degree murder in state court for his role in the crimes. The witness, Jessie Jacobus, testified during the first week of the trial that Mr. Wilson shot the two detectives in the head.

Mr. Savitt reminded the jurors that Jacobus had seemed evasive during cross-examination and would not answer even the most straightforward questions at times. In all, Mr. Savitt counted 138 instances in which Jacobus said he did not understand what he was being asked.

“It shows he’s a wise-aleck,” Mr. Savitt said. “It shows that he is still a hustler.”

Mr. Savitt asked the jury to question the narrative Jacobus gave of how the murders occurred.

“We have no eyewitness but Jessie Jacobus to tell us what was going on” in the minutes leading up to the murders, Mr. Savitt said.

During the summations, Mr. Wilson gave little sign of emotion. As Mr. Savitt recounted a forensic pathologist’s testimony about the body of one of the detectives, Mr. Wilson brought a hand to his mouth and yawned. Prosecutors have suggested that Mr. Wilson knew the two men were police officers.