Street-Hustler Bartleby

Michael Brick in court: By his own description, the contract Jessie Jacobus signed with prosecutors offers a warm letter to his sentencing judge in return for his pledge to "be truthful, give details about every crime I've ever done in my life, go to the hearings and testify."

Though the agreement does not address how he is to behave on cross-examination, Mr. Jacobus appeared as a man transfigured yesterday in Federal District Court in Brooklyn when a defense lawyer questioned him about the killing of two undercover detectives.

Gone was the compliant, forthcoming, soft-spoken, hulking young man who had patiently translated street terminology, who had explained gang hand signals and who had…