Two Republican state representatives are asking the chairman of the House Committee on Post Audit and Oversight to investigate the “rigged hiring system” at the Probation Department and make referrals to the House Ethics Committee if any lawmakers were involved.

The letter from Reps. James Lyons Jr. of Andover and Marc Lombardo of Billerica summarizes some of the evidence presented at the trial of former Probation commissioner John O’Brien and two of his top aides, focusing heavily on House Speaker Robert DeLeo’s involvement in the case. Federal prosecutors named DeLeo an unindicted coconspirator, a charge DeLeo has called false and unfair. O’Brien and former aides Elizabeth Tavares and William Burke were convicted in July and sentenced last week. O’Brien received 18 months, Tavares three months, and Burke was placed on probation. O’Brien was also fined $25,000 and Tavares and Burke were each fined $10,000.

Lyons and Lombardo urged the Post Audit committee to investigate how the rigged hiring system was allowed to operate for a decade, to estimate its cost to taxpayers, to explore why other employees at Probation didn’t blow the whistle on the practice, and to determine whether the hiring practices at a new facility in Clinton were standard throughout the agency.

DeLeo, according to testimony at the trial, told several colleagues in the Legislature about job openings at the new Clinton facility and urged the lawmakers to recruit candidates for the positions. Several of those referred by the lawmakers were hired by O’Brien sight unseen. One of those lawmakers who referred a person for a job at the Clinton facility was Rep. David Linsky of Natick, the chairman of the House Committee on Post Audit and Oversight, to whom Lyons and Lombardo wrote their letter.

The other lawmakers cited in the letter because of their involvement with the jobs at the Clinton facility were Reps. Harold Naughton Jr. of Clinton, James O’Day of West Boylston, Michael Moran of Brighton, Kevin Honan of Brighton, Anne Gobi of Spencer, and former Rep. Robert Rice of Gardner.

“This Probation scandal goes right to the heart of what goes on in the Legislature,” said Lyons in a telephone interview. He added that Democrats in Massachusetts are constantly saying they favor a transparent and open political process. He said a Post Audit investigation into Probation is the best way to prove they mean it.

Linsky said his committee is reviewing the letter from Lyons and Lombard and declined further comment.