Federal prosecutors and lawyers representing three former Massachusetts probation department officials are preparing for opening statements in a trial that could include testimony from some big names in state government.

Former commissioner John O'Brien is charged along with Elizabeth Tavares and William Burke with rigging the agency's hiring process to favor politically-connected job applicants, often at the expense of more qualified candidates.

Testimony is expected to begin after opening statements on Thursday.

A jury that was seated on Wednesday was instructed by U.S. District Court Judge William Young to avoid exposure to news coverage, including on social media, of the trial that could last two months.

A list of possible trial witnesses reads like a Who's Who of Massachusetts politics, including dozens of past and present state legislators, public officials and judges.