NORTH ATTLEBORO -- North Attleboro Electric has filed a lawsuit against the accounting firm Grant Thornton LLP, alleging that the company failed to protect electric ratepayers from the misuse of $4 million in bond funds.

The lawsuit was filed Monday in Bristol County Superior Court.

Grant Thornton was the accounting firm that audited the electric department's books from 1998 to 2001, when the bond money was spent.

`` As the claims in this lawsuit show, it is proper, appropriate and unfortunately, necessary that NAED seek to protect our ratepayers by seeking appropriate financial damages from Grant Thornton for its betrayal of the public trust as set forth in the lawsuit,'' Electric Commission Chairman Thomas Corrigan said.

North Attleboro Electric has hired attorneys Albert Farrah Jr. and John Kelleher of Boston to handle the case, with the contract capped at $250,000, plus expenses. The lawsuit alleges that Grant Thornton failed to use reasonable care when auditing the electric department's books. The lawsuit also charges that Grant Thornton knowingly and fraudulently concealed from the town its knowledge that the bond funds were spent inappropriately.

Representatives from Grant Thornton said the company would make no public comment on the matter.

`` It's with regret that we filed the lawsuit,'' electric department General Manager James Moynihan said.

`` The intent is to hold Grant Thornton accountable for basic accounting failures they should have picked up -- expenditures the ratepayers of North Attleboro will be paying for through the year 2018.''

The $4 million in bond money was spent on a failed Internet venture that will ultimately cost the town's ratepayers $8 million, including losses and interest payments.

The bond money allegedly was spent by North Attleboro Electric's former management without authorization from town meeting.

The state inspector general said in a report that Grant Thornton failed to exercise reasonable care when performing audits for North Attleboro Electric between 1999 and 2002, and recommended that the electric department consider taking legal action against the firm.

AMY DEMELIA can be reached at 508-236-0334 or at ademelia@thesunchronicle.com.