All seven members of the Hanson Recreation Commission recently resigned their positions, citing frustration with a long-running investigation into the operation of the town-owned Camp Kiwanee.

The sudden mass exodus of the volunteers has cast the spotlight on the probe, whose specific purpose has not been publicly disclosed by town officials.

Jim Hickey, then the commission’s chairman, resigned his seat at the board’s Aug. 11 meeting. The six remaining members then quit in an Aug. 15 letter to the Board of Selectmen and Town Administrator Michael McCue.

In the letter, which Hickey said also reflected his views, the members wrote that the panel’s ability to function effectively “has been severely compromised by the prolonged investigation of Camp Kiwanee.’’

“There has been no feedback, support, or guidance to the Recreation Commission by the Town Administrator, Board of Selectmen and/or Town Counsel regarding the status of the investigation or when it will end,’’ charged the members, Jan Agius, Tricia Dransfield, Sheila Morse, Susan Lonergan, Fran O’Kane, and Raymond Slayton.

The group added that “since the audit/investigation began in December 2015, we have sensed an omnipresent shroud of secrecy and impending doom outside of our control which we have been obligated . . . to ‘not speak to anyone about’ ’’ and had been left out of decisions regarding Camp Kiwanee.

Hanson acquired the 64-acre property off Indian Head Road from the Campfire Girls of Boston in 1979. It includes a year-round function facility and cabins. The Recreation Commission oversees the camp as well as an adjacent town beach on Maquan Pond.

In a written statement to the Globe Tuesday, McCue confirmed his office and selectmen received the members’ resignations on Aug. 15.

“When it was brought to the attention of the Board and this office that there were issues with the way business was being conducted at Camp Kiwanee, an investigation was compelled and it began in late March,’’ said McCue, who began as town administrator in May. “With few exceptions, Commission members and Commission employees, including those of longstanding tenure, have been less than fully cooperative. Dealing with the lack of cooperation has delayed the conclusion of the investigation.’’

He said town leaders “regret that it has come to this’’ but respect the members’ decision. “Notwithstanding the recent and past resignations, the inquiry will continue to its conclusion,’’ he said.

Hickey, in an interview, denied that the commission had been uncooperative.

“It’s very sad and it’s very frustrating,’’ he said of the investigation. “This started out as an audit and somehow got turned into a full-blown investigation. . . . It’s just so tragic because it didn’t have to happen this way.’’

McCue said the inquiry is being conducted by the town counsel with his assistance. He said to date the probe, due to be completed the end of September, has cost the town about $28,000.

John Laidler can be reached at laidler@globe.com.