NEW ORLEANS — A former administrator at the troubled New Orleans jail pleaded guilty Thursday to a federal charge arising from his role in a private security business that sometimes hired off-duty deputies for security details.

Gerald Ursin Jr., 62, pleaded guilty to a single count of conspiracy to commit wire fraud. He had been charged earlier this year, after resigning from the Orleans Parish Sheriff’s Office.

Prosecutors filed documents Thursday outlining more than $25,000 worth of fraudulent invoices and checks benefiting Ursin. The crimes involved his work for a security business run by another former sheriff’s office official, Roy Austin, who pleaded guilty in May.

Prosecutors said Austin fraudulently billed clients, including a Mardi Gras parade club, for “ghost employees” who did not actually work.

Austin funneled money from the scheme to Ursin by writing checks to selected members of Ursin’s family, prosecutors said.

The charge against Ursin followed the release of a state audit in April that raised questions about Austin’s business and Ursin’s role in it.

Ursin resigned after the audit was made public. He was charged in federal court on the same day Sheriff Marlin Gusman, who had come under harsh criticism for continued violence at the jail, agreed to cede authority to a “compliance director.” That agreement headed off the possibility that a federal judge would strip him of his authority to run the jail because of slow compliance with court ordered reforms.

Gary Maynard, a former Maryland corrections official, was chosen for the job in August. His appointment was approved Thursday by U.S. District Judge Lance Africk.