A former employee who embezzled $51,500 from the Montville Water Pollution Control Authority admitted Monday in New London Superior Court that she violated the terms of her probation by failing to make full restitution to the town agency.

"I'm sorry," said 57-year-old Linda K. Rivera of Willimantic.

She had worked for the WPCA since 1989 and was its deputy administrator when she was placed on leave in 2005 after auditors discovered a series of shortfalls. Rivera had been taking check payments from customer accounts to cover for cash she had stolen, according to court testimony.

Rivera repaid the $51,500 when she was sentenced in 2007 to three years in prison, suspended after 90 days probation and five years served. The authority was seeking an additional $55,760 to cover the cost of the investigative audit. Rivera paid only $25 a month while on probation, for a total of $1,195, according to an arrest warrant affidavit.

Her admission of a probation violation, which will be listed on her criminal record along with the felony conviction for first-degree larceny, put an end to the case. Five years is the maximum period of probation for the larceny charge.

Prosecutor Lawrence J. Tytla said he had been in touch with town officials through their attorney, Michael Blanchard.

"They're not happy," Tytla said. "They would like to get full restitution but there is not much they can do. They did get a substantial up front payment."

Judge Susan B. Handy said she could understand why town officials were disappointed while noting that they did recover a substantial amount of money "as these cases go."