WORCESTER — Opening statements are scheduled Monday morning in the trial of an 82-year-old Salisbury man charged with murder and armed robbery in the shooting death of an armored truck guard during a holdup 27 years ago at a supermarket on Lincoln Street.

Prosecutors allege that Ralph DeMasi was one of five men who took part in the May 18, 1991, robbery at the Shaw's supermarket at 490 Lincoln St. and was one of the gunmen who opened fire on 52-year-old armored truck guard Edward P. Morlock Sr. of Athol, who died after being shot multiple times. Three of the participants in the holdup have since died, according to prosecutors.

Mr. DeMasi, who was indicted on the charges in 2016, has denied the allegations against him and pleaded not guilty.

A 16-member jury, including four alternate jurors, was chosen Wednesday and Thursday to hear the Worcester Superior Court case. Twelve jurors will deliberate and the alternates will be chosen at random immediately before deliberations begin. It is expected that the trial will include about five days of testimony.

Among those expected to testify against Mr. DeMasi is Ronald Martel, formerly of Worcester, who has said he was the getaway driver for the robbery and has been granted immunity from prosecution in exchange for his testimony, according to court records.

The lawyers in the case were allowed to question panels of prospective jurors on a wide range of topics ranging from the presumption of innocence to evaluating the testimony of a witness who has been granted immunity.

Assistant District Attorneys Terry J. McLaughlin, Brett F. Dillon and Ellyn H. Lazar are prosecuting the case.

Mr. DeMasi is represented by lawyers Michael S. Hussey and Paul Rudof.

Judge Janet Kenton-Walker will preside over the trial.