A defendant in a fraud case involving the theft of millions of dollars or more from a prominent Morgan City family pleaded guilty Wednesday in exchange for sentencing leniency.

Donna Sue Peveto pleaded guilty to 123 counts of racketeering and theft, and agreed to testify at trials of her co-defendants Armond Duhon and his wife, Karen Duhon. The plea agreement, reached with prosecutors with the 16th District Attorney’s Office, states Peveto’s prison sentence will be no more than 25 years.

Prosecutors said Peveto, the Duhons and James Scott Tucker were engaged in a scam that ran for years and took advantage of the trust that Peter V. Guarisco placed in Tucker to run his family’s holding company, Capital Management Consultants Inc. Guarisco hired Tucker in 1977, and Guarisco’s children kept Tucker in charge of the company after the elder Guarisco died in 2005.

It was a scheme, Guarisco’s family now believes, that bilked the family of millions of dollars in cash, art and property over a period of decades, the family alleged in a lawsuit.

According to the lawsuit, the success of the long-running scam relied on the quiet confederacy of the Duhons, Peveto and Tucker. Guarisco and his children regarded Tucker as a trusted family member, the lawsuit states, until Tucker died in 2014 and the scheme unraveled to expose the fraud.

Efforts to talk to a member of the Guarisco family were unsuccessful Wednesday. Bob Fuhrer, attorney for Karen Duhon, declined to comment.

Ed Jones, attorney for Armand Duhon, said “Obviously, Ms. Peveto did what (she felt) was in her best interest.”

The District Attorney’s Office charged the Duhons, Peveto and two associated companies with 100 counts of money laundering, one count of racketeering and 354 counts of theft over $1,500.

Karen Duhon, Peveto and Tucker are accused of committing the thefts when they worked at Capital Management Consultants; Armond Duhon is accused of using his company, A-B-C Siding of Morgan City, to steal money from the Guarisco company.

Peveto on Wednesday admitted in a Franklin courtroom to being part of a criminal enterprise. She also admitted to conspiring with the Duhons and Tucker to steal cash from the company and art from the Guarisco family’s art galleries in Washington D.C., Atlanta and New Orleans.

Peveto’s attorney, Thomas Alonzo of Lafayette, said the Duhons’ trial is scheduled for April.

Alonzo said talks with the District Attorney’s Office have been underway for a while about Peveto pleading guilty to some charges in exchange for her testimony.