A Medford man plead guilty to charges of forging 3,000 counterfeit MBTA passes, an operation that earned him more than $60,000 and ripped off an estimated $225,000 from the T.

Casey Kolenda, 28, pleaded guilty in Middlesex Superior Court on seven counts of counterfeiting. Judge Thomas Billings gave Kolenda three years in state prison and three year probation.

“This scheme resulted in significant revenue loss for the MBTA and was patently unfair to riders who paid the full cost of their transit passes,” Attorney General Maura Healey said in a press release. “Schemes such as this one, in which an individual commits crimes for personal gain at the expense of the public, will not be tolerated.”

T police started investigating this situation when they found hundreds of unauthorized tickets in use on the train and bus lines in August 2013. The Attorney General’s Office and the State Police joined the investigation in September 2013. They tracked down multiple legitimate monthly LinkPasses used to create hundreds of bogus tickets. Kolenda created fake $70 monthly passes between October 2013 and March 2014 by copying the electronic data stored on the LinkPass magnetic strip.

He then downloaded the magnetic strip data of hundreds of T stored-value cards and applied contact paper with encoded data that would allow users to get through the fare gates without any issue.

Kolenda was arrested in March 2014 in Medford and was indicted by a Statewide Grand Jury in July 2014. At the time of his arrest Kolenda had almost $7,000 cash on him and over 60 counterfeit April 2014 LinkPasses.

State Police executed a search warrant at his home and seized additional counterfeit April 2014 LinkPasses, hundreds of MBTA five-cent cards, three skimmers and the material and computer equipment used to manufacture the counterfeit passes.

The T estimates that Kolenda is responsible for over 3,000 counterfeit MBTA passes in circulation from October 2013 through March 2014.

The joint investigation revealed that these counterfeit passes bearing the electronic data of the original were distributed and used on a monthly basis by T riders, sometimes more than 15,000 times in one month. Investigators estimate that the lost revenue attributable to the counterfeit tickets manufactured and distributed by Kolenda was in excess of $225,000.