The nonprofit Friends of Hanauma Bay says the city continues to “intentionally and persistently” misuse money collected at the site to pay for operations at other East Honolulu facilities despite court mandates requiring the money be used at the nature preserve only.

The law firm Alston Hunt Floyd & Ing, which represents the Friends, said it will pursue further legal action unless it hears back from the city by Oct. 10.

Among the demands are an immediate audit of fund finances; repayment to the fund, with interest, of all misused appropriations; and an annual independent audit of the fund.

The city issued a statement late Monday saying it has strived to “provide Friends of Hanauma Bay with accurate and responsive information.”

In 2002, the U.S. District Court ruled it was wrong for the city to use money from the fund to pay for operations, maintenance and improvements of park facilities near Hanauma Bay Nature Preserve, the attorneys pointed out in a seven-page letter dated Friday.

The same court also determined that the city needed to refund the Hanauma Bay account the $3.17 million that had been used for other facilities, the letter said. “There is an urgent need for the City and County to correct the continuing misuse of admission fees paid by visitors to Hanauma Bay.”

The city’s current operating budget projects $7.5 million in revenues derived through nonresident admissions as well as parking fees and equipment rental during the 12 months ending June 30, 2017.

The letter said research by the Friends found that money has gone to: purchase vehicles used for other parks; compensate parks employees for work done elsewhere; collect refuse from adjacent parks; and upkeep maintenance and supplies at adjacent parks.

The City Council approved funding for a Hanauma Bay carrying-capacity study that has yet to begin, the letter said. It would be the first done at the bay since 2000, despite a requirement that such studies be undertaken under the 1996 ordinance that set up the fund.

The state Board of Land and Natural Resources in 2001 approved a conservation district use permit for the city’s management of the preserve; it requires the city to update its carrying capacity information annually, the letter said.

The city, in its statement, did not say whether funds are still being diverted away from Hanauma Bay.

“Many of the concerns in the letter relate to issues that occurred in past decades and must be further researched,” the city said in an email. “The city continues to work toward preserving the Hanauma Bay Nature Preserve for future generations and appreciates the efforts of all concerned.”

In 2014, the Council shelved a resolution urging that a semiautonomous agency manage, operate and maintain the bay and have exclusive authority over the Hanauma Bay fund after receiving assurances that the Department of Parks and Recreation would look into where the fund’s money was going.

Mayoral challenger Charles Djou said Monday that “the neglect of Hanauma Bay by the administration is more than typical bad management, it hurts one of the most amazing natural resources on our planet.”

Djou, in a statement, pointed out that as a City Council member, he had pushed successfully for an audit of the fund.

The city should look to a public-private partnership to take over and manage the bay, Djou said, adding that it was an idea he proposed many years ago and is supported by the Friends.