A 31-year-old Lawrence man convicted of voluntary manslaughter is fighting a request from prosecutors to withdraw an earlier agreement to trim four years from his sentence in exchange for testimony against a co-defendant.

Branden Bell, the new defense attorney for Major C. Edwards Jr., said Monday his client held up his end of the bargain when he testified in the March trial against co-defendant Durrell Jones. Edwards had pleaded guilty in 2010 to voluntary manslaughter related to the Oct. 14, 2006, shooting death of Lawrence hip-hop artist Anthony Vital, and Edwards testified at Jones’ trial that he saw Jones shoot Vital to collect on a drug debt. Edwards said he felt remorse for leading Jones, 24, of Kansas City, Kan., to Vital but contended he didn’t pull the trigger.

The jury was unable to reach a unanimous verdict in Jones’ trial, and District Attorney Charles Branson announced Aug. 2 his office would not seek a second trial against Jones and dismissed the charges due to concerns with Edwards’ credibility.

Branson alleges Edwards made statements to a fellow inmate after the trial that contradicted his testimony, including allegations that Edwards said he shot Vital and that Edwards and Jones did discuss killing Vital prior to the murder. Edwards in court filings has denied those allegations.

Prosecutors are asking a judge to sentence Edwards to an 18-year prison sentence concurrently with a federal weapons conviction, but the defense contends Edwards should still be eligible to receive four years off of his sentence.

“Our position is that he did come and testify truthfully,” Bell said.

Chief District Judge Robert Fairchild has scheduled an Oct. 12 hearing on the matter.