KILLING UNNO WID DUDUS NEWS

In testimony on Tuesday, Jermaine Cohen, 37, a former member of Mr. Coke’s gang who has cooperated with the authorities, offered vivid testimony about a half-dozen killings. He said that Mr. Coke disappeared into the jail with a power saw, hatchet or gun, and appeared to calmly dispatch those who had stolen from his group, not paid him, or otherwise violated his rules.

Mr. Cohen said he remained outside the jail, but heard what was happening. In the case of one man, he mimicked the sound of a power saw that he observed Mr. Coke take in with him.

“One scream, and then I don’t hear nothing more, sir,” Mr. Cohen told the prosecutor, John T. Zach, who was questioning him.

Mr. Cohen, who wore an orange prison jumpsuit and who is serving a federal sentence for illegal re-entry and other charges, testified that his job was to clean up after his boss. He said that he would wait until Mr. Coke left the jail, often with bloody hands and sneakers, and then he would enter, and find butchered remains and blood on the floor.

Mr. Cohen, who has also pleaded guilty to additional gun and drug charges, admitted that he was hoping for leniency at sentencing in return for his cooperation. Mr. Coke, meanwhile, sat impassively at the defense table, watching as Mr. Cohen testified.

During cross-examination, one of Mr. Coke’s lawyers, Stephen H. Rosen, tried to undermine Mr. Cohen’s credibility, citing his use of multiple false identities and leaping on inconsistencies in his testimony. “You’ve got a great memory, sir, for things that happened 15, 16, 17 years ago, but you can’t even tell us what you pled guilty to” under a different name in 2009, Mr. Rosen told the witness at one point.

Mr. Rosen said during a break that the judge would give the defense time to investigate and “determine the validity” of Mr. Cohen’s statements.

Mr. Cohen is one of two former high-level members of Mr. Coke’s group, called the Presidential Click, who have been cooperating with the investigation by prosecutors and the Drug Enforcement Administration, the government has said.

On Monday night, prosecutors filed a 26-page statement from a former senior adviser to Mr. Coke, identified only as John Doe, who said he had been a bodyguard and close aide to Mr. Coke’s father, Jim Brown, in the 1980s, when Mr. Brown ran what prosecutors say was the organization that his son, Mr. Coke, eventually took over.

“Over time, I became, in essence, a trusted senior counselor to the organization,” the former adviser wrote. Prosecutors indicated that the former aide would not be called to testify, but said his statement would be used to try to bolster the government’s case at the hearing, which continues on Wednesday.

Although the hearing resembles a minitrial, it differs in significant ways. For one thing, the standard of proof for prosecutors to make their case is much lower than in an actual trial.

Daniel C. Richman, a Columbia law professor and former prosecutor, said that despite the narrow range in which Mr. Coke’s sentence was likely to fall, prosecutors might be trying to do more than just lock in the highest number.

“They may well have their eye on the audience in Jamaica,” he said, “as well as on the particular victims of the crimes beyond those to which he pled. This becomes an authoritative documenting of the extent of Coke’s crimes.”

A version of this article appeared in print on May 23, 2012,