Federal authorities have ramped up an investigation into the Louisiana State Troopers Association, delivering a series of grand jury subpoenas this week to the nonprofit organization's board of directors, according to sources familiar with the matter. 

Col. Mike Edmonson, the State Police superintendent, said Thursday that the FBI has notified him "that they would be interviewing some of our guys" regarding the association, a group of current and retired troopers that has drawn mounting scrutiny — and a State Ethics Board fine — in light of its unlawful political contributions.

"We have cooperated fully with every investigation related to our association and will continue to do so," said Jay O'Quinn, president of the association. "We eagerly anticipate the opportunity to bring all the facts forward to correct the misinformation and disinformation that have been purported."

Maj. Doug Cain, a State Police spokesman, noted that the troopers association is "independent of the department" and that the State Police, "as an agency, has not been served with any subpoenas regarding our operations."

But sources familiar with the inquiry said more than a dozen people, including some high-ranking State Police officials, received subpoenas this week compelling them to testify before a federal grand jury.

"They're stirred up right now," one source said, referring to the State Police.

The sources spoke on the condition of anonymity because they were not authorized to discuss the ongoing investigation. 

The months-old inquiry appears to be focused in large part on contributions the State Troopers Association made in 2014 and 2015 to 10 political candidates, including Gov. John Bel Edwards, and the House Democratic Campaign Committee.

Troopers, as classified state employees, are forbidden from making political contributions. But the State Ethics Board fined the troopers association $5,000 in January after it found the group had used its executive director, David T. Young, as a "straw donor" to make more than $17,500 in political contributions. 

Nearly $10,000 of the money went to Edwards, who also received a rare endorsement from the association during the 2015 gubernatorial campaign.

A spokesman for the governor said last year that Edwards had not been aware that the troopers association was reimbursing Young for the contributions made in his name. He said Edwards returned the money after learning its source. 

Floyd Falcon, the association's general counsel, declined to say whether troopers had been subpoenaed, but he questioned how the feds would have jurisdiction over state election contributions.

A spokesman for the FBI's New Orleans office declined to comment. 

The federal inquiry, which was first reported Wednesday by Louisiana Voice, a state politics blog, is also said to be examining the troopers association's collection of dues and how it spends that money.

The association, which represents 97 percent of current troopers and a large number of retired troopers, is a private benevolent 501(c)(5) organization that collects dues from its membership. The group also raises outside funds and, in many ways, functions as a union, donating to special causes and helping troopers during times of hardship, such as last year's devastating floods. 

While the State Police sought to distance themselves from the investigation, the federal subpoenas were issued at a time of turmoil for the agency.

Edwards last month ordered an audit of State Police travel after The Advocate reported that four troopers charged state taxpayers for a lavish detour they took last year to Las Vegas and the Grand Canyon as they drove to a law enforcement convention in California. The State Police also are conducting an internal investigation into the trip and recently altered their overtime policies in the wake of the revelations. 

U.S. Sen. John Kennedy, R-Louisiana, called for Edmonson's resignation after news of the Las Vegas trip surfaced, accusing the superintendent of squandering taxpayer dollars. Edmonson said he was appalled by Kennedy's comments and has no intention of stepping down from a position he's held for nine years. 

Rafael Goyeneche, president of the Metropolitan Crime Commission, noted that while the LSTA is a nonprofit organization, it is composed of current and former state troopers. The federal inquiry, he said, is "indicative that this organization has lost its way and that this investigation is probably moving in other directions as well."

"If the leadership of that organization thought it was appropriate to funnel campaign contributions, it raises questions about their judgment and how they're using the association's assets," Goyeneche said. 

Follow Jim Mustian on Twitter, @JimMustian.