The CEO of a nonprofit organization that supports the National Park Service’s operations in Pearl Harbor has been suspended while the group’s board investigates allegations made in an anonymous letter.

Pacific Historic Parks Board of Directors member and spokesman Jim Boersema said Wednesday Ray L’Heureux was placed on paid administrative leave last week.

It wasn’t clear what allegations were made in the letter, which was sent to board members.

“We have an obligation to look into things if somebody writes them. So we’re doing what’s required. And we’ll treat Ray fairly,” Boersema said. Most board members believe L’Heureux has been doing “a pretty good job,” he said.

L’Heureux said he couldn’t comment as it was a personnel issue, even though it involved him.

L’Heureux has been CEO of Pacific Historic Parks since late 2015. He served in the Marine Corps for 30 years, including stints as a helicopter pilot and commander of Marine Helicopter Squadron One, which flies the president. Before joining Pacific Historic Parks, he was an executive with the Hawaii State Department of Education.

Pacific Historic Parks runs a gift shop at the Pearl Harbor visitors’ center and raises money to support the USS Arizona Memorial. The Park Service relies on funds from the nonprofit to help maintain the national landmark, which is visited by 1.8 million people each year.

Pacific Historic Parks also supports public park and memorial sites on Molokai, Guam and Saipan.