When federal prosecutors accused three men of a loan-sharking scheme last week, the authorities vividly described how the men used threats of violence to ensure that they would be repaid.

One debtor reported that someone fired a gun at his car as he was backing out of his driveway in Queens, according to court filings. Another debtor said two of the men, Daniel Hanley and his associate, would display firearms when he met with them to pay back a piece of what he owed.

But the most tantalizing accusation was not of violence but of affiliation: prosecutors described Mr. Hanley, 47, as a member of the Westies, the Irish-American gang in Hell’s Kitchen that specialized in extortion and in dismembering their victims.

When Mr. Hanley, who is in federal custody in the case charged with extortion, heard that he was being labeled a member of the Westies, “he was incredulous,” said his lawyer, Marion Seltzer.