The third suspect in a string of catalytic converter thefts pleaded guilty in Suffolk Circuit Court on Thursday.

Nicholas Edward Villi, 26, of Windsor, pleaded guilty to 14 counts stemming from the rash of thefts.

He and two others, Tiffany Nicole Holt and David Christopher Bone, were arrested in July after a school resource officer spotted them near a teacher’s car at King’s Fork Middle School, according to police. Police stopped their car on Lake Prince Road after learning that the catalytic converter on the teacher’s car had been stolen.

Villi signed a plea agreement in which 13 of the original 27 charges were dropped. He pleaded guilty to six counts of grand larceny, five counts of larceny with intent to sell, one count of attempted grand larceny, one merged count of conspiracy to commit larceny and one merged count of possession of burglary tools.

The trio committed numerous catalytic converter thefts between April and July this year. Some of the thefts were from vehicles in residential areas, and some were from vehicles in parking lots.

The catalytic converter is an expensive part of a vehicle’s emissions control system. It contains several precious metals.