BOSTON — A federal extortion case involving Boston city officials pressuring music festival organizers to hire union workers may come down to jury instructions.

Kenneth Brissette and Timothy Sullivan allegedly had Crash Line Productions, the organizers of the Boston Calling music festival, hire union labor for a Sept. 2014 event.

The Boston Globe reports prosecutors are expected to urge US District Judge Leo T. Sorokin to change his plans on how to instruct the jury in a trial set to begin March 26.

Sorokin has previously said he plans to tell jurors they must find Brissette and Sullivan benefited personally from the hires.

Prosecutors say they cannot meet the qualifications the judge has established for a conviction.

They argue that the men were guilty of extortion when they forced the company to give the jobs to favored constituents— unions.

Information from: The Boston Globe,