WORCESTER - One of four people charged in the 2015 shooting death of 18-year-old Sam Castro was sentenced to time served and placed on probation Wednesday after pleading guilty in Worcester Superior Court to assault with a dangerous weapon.

Manslaughter and carrying a firearm without a license charges against Qwandre Bath, 19, of 104 Stanton St., were dropped by prosecutors as part of a plea agreement in the case, according to court records.

As recommended by Bristol County Assistant District Attorneys Dennis H. Collins and Michael Sheehan and Mr. Bath's lawyer, Jaclyn Greenhalgh, Judge Daniel M. Wrenn sentenced Mr. Bath to 18 months in the House of Correction with 323 days to be served on the assault with a dangerous weapon (firearm) charge. The balance of the sentence was suspended for 18 months with probation and Mr. Bath was given credit for 323 days served awaiting trial.

He was placed on GPS as a condition of his probation.

The charges of manslaughter and carrying a firearm without a license were nol prossed by prosecutors. A nol pros is an entry in the court record reflecting a prosecutor's decision not to proceed with a charge once it has been brought.

Mr. Bath, whose first name is also listed as Qwandry in court records, was one of four people charged in the May 12, 2015, slaying of Mr. Castro, a former standout football player at North High, who was fatally shot on Frederick Street.

The alleged gunman, Emil Encarnacion, 19, of 16 Oread Place and one of his co-defendants, Connor Ferguson, 20, of 8 Saliminen Drive, Leicester, were charged with murder in the fatal shooting. A fourth defendant, Jovante M. Daye, 20, of 174 Eastern Ave., is under indictment on charges of murder, assault with a dangerous weapon, carrying a firearm without a license and being an accessory, after the fact, to murder.

Jury selection for Mr. Encarnacion's trial was scheduled to begin Thursday, but the trial has been postponed at the request of his lawyer, Joan M. Fund, court records show. Mr. Encarnacion's case has been continued to Oct. 25 for a status report. Mr. Daye is also awaiting trial.

Mr. Ferguson's case was scheduled for a plea hearing April 13, but Judge Wrenn closed the courtroom to the press and public for the proceeding.

According to motions filed in the case by Ms. Fund on behalf of Mr. Encarnacion, Mr. Ferguson, whom she described as a "cooperating witness" in the case, pleaded guilty to a reduced charge of manslaughter and is expected to be sentenced to 8½ to 12½  years in state prison in exchange for his cooperation.

Paul R. Jarvey, a spokesman for District Attorney Joseph D. Early Jr., said Thursday that Mr. Early brought the Bristol County prosecutors into the case because of "a potential, perceived conflict of interest." He declined to elaborate.