Prosecutors in the so-called South Capitol Street massacre told a D.C. jury Thursday to focus on the testimony of one of the men who admitted to being one of the triggermen.

"You are given a window" into one of the District's deadliest shootings, prosecutor Bruce Hegyi said during closing arguments of the trial that has gone on since February.

The trial has included the testimony of more than 100 witnesses and featured more than 1,000 pieces of evidence.

Hegyi told the jury to believe the tearful testimony of Nathaniel Simms, who described how he fired an AK-47-style weapon into a crowd mourning the death of 20-year-old Jordan Howe.

Two others in the van also fired weapons, and the result was the death of three more young people, Hegyi said.

Simms, who pleaded guilty to lesser charges, agreed to cooperate with authorities and testified during the trial.

Hegyi argued to the jury that Simms was credible. Simms had described how Orlando Carter received a call from his brother about being robbed and how some of the defendants retrieved weapons and planned to retaliate. Other witnesses' testimonies and phone records support Simms' account.

"This is powerful corroboration," Hegyi said.

The defendants -- Sanquan Carter, 21, his brother Orlando Carter, 22, Jeffrey Best, 23, Robert Bost, 23, and Lamar J. Williams, 23, -- remained silent during the final arguments. Each could face life in prison.

The prosecution will continue its closing arguments Monday, and then lawyers for each of the defendants will take their turns.

The defendants clearly planned to retaliate following the theft of a bracelet by shooting and killing, prosecutors say.

Sanquan and Orlando Carter along with Best are accused of killing Jordan Howe outside an apartment building on the 1300 block of Alabama Avenue SE on March 22, 2010.

On March 30, the day of Howe's funeral, prosecutors say Orlando Carter and his friends piled into a rented minivan to seek revenge. They shot one rival in a housing development in Southeast and then saw a crowd of Howe's friends gathered on South Capitol Street, prosecutors have alleged.

Killed were Brishell Jones, 16, DaVaughn Boyd, 18, and William Jones, 19.