Lawyers for the Uzbek man charged in the truck attack on a crowded Manhattan bike path that killed eight people on Halloween said on Wednesday that their client would plead guilty and accept life imprisonment without parole if prosecutors agreed not to seek the death penalty.

The proposal came in an exchange of letters to Judge Vernon S. Broderick of Federal District Court in Manhattan, in which prosecutors were seeking a firm trial date for the defendant, Sayfullo Saipov, arguing that victims and witnesses needed closure, and Mr. Saipov’s lawyer said the best way to obtain closure was through such a plea deal.

The government has not yet said whether it would seek the death penalty for Mr. Saipov, 29, who was indicted on eight capital counts and other charges in the Oct. 31 attack, the deadliest terror attack on New York City since Sept. 11, 2001. Mr. Saipov has pleaded not guilty.