MONROE — The former president of a labor union for corrections officers pleaded guilty last week to stealing $66,300 from union coffers.

William R. Reilly Jr., 36, of Carlstadt, pleaded guilty to a count of theft during a hearing before Superior Court Judge Frederick P. DeVesa at the Middlesex County Courthouse in New Brunswick on April 1, according to Middlesex County First Assistant Prosecutor Julia McClure.

Reilly, who worked as a corrections officer at the New Jersey Training School for Boys in Monroe, admitted stealing the funds from the Juvenile Justice Correction Officers Association, PBA Local 367. He admitted the thefts occurred between September 2007 and July 2009.

During the court hearing, Reilly waived his right to a presentation of the case to a grand jury and pleaded guilty following negotiations with Middlesex County Assistant Prosecutor Manuel Sameiro.

Under the terms of the plea agreement, Reilly faces up to three years in prison when he is sentenced June 10. Reilly also will be required to pay back the stolen money. He has already paid about $25,000.

In addition, he must forfeit his job as a corrections officer and will be barred from holding any public job in the future.

Reilly was charged March 4 following an investigation by Sgt. Pamela Jeffrey of the Middlesex County Prosecutor’s Office. The charge was filed after it was determined that Reilly, while serving as union president, withdrew various amounts of cash from automated teller machines and made purchases with a union debit card.

The investigation began after union officials reported the thefts to the Middlesex County Prosecutor’s Office.