Earlier this year, a CBS News investigation found the Wounded Warrior Project spends far less of its donations on veterans compared to others. And if we were surprised, so were some major donors.

With two sons serving in Iraq, raising money for Wounded Warrior Project was more than a cause for Fred and Dianne Kane. It was a calling.

Since 2009, the Kane's charity Tee-off for a Cause raised $325,000 for WWP through golf tournaments in the Carolinas. WWP even honored Fred Kane with an award for being a VIP donor.

But allegations that only a little over half of donations went to help wounded vets came as a blow.

"Hearing that there was this waste of money, donor dollars that should have been going to servicemen and women that were injured, and that it was spent on their having a good time -- it's a real disappointment," Dianne Kane told CBS News.

Fred and Dianne Kane CBS News

Wounded Warrior Project's tax forms show spending on conferences and staff meetings grew to $26 million by 2014. But the charity insists those expenditures qualify as programs and services.

Outraged, the Kanes cancelled this year's benefit tournament and started a petition on Change.org calling for a public audit. Fred also called senior management, and said he thought CEO Steven Nardizzi should be fired.

"Where is this guy? You lead from the front, good or bad, you don't hide," Fred Kane said. "I don't understand how an organization that has many veterans who value honor and service and chain of command can be led by a guy like that."

CBS News has learned Fred Kane is one of several major donors who are ending their support, and he wants answers from the group's board of directors.

Sources with direct knowledge of the charity's operations said the board signs off on all of the charity's major spending, including expensive staff retreats.

Those sources also said the board has spent donor dollars on its own meetings at five-star hotels including the Beverly Wilshire in Los Angeles and the Waldorf Astoria in New York.

And when board members questioned spending decisions and executive salaries, their concerns were ignored.

CBS News tried to speak with each board member in person, but they declined.

"I feel like I am representing all these people who have donated over the years, all these seniors over 65 sending $19 month, all these people on fixed incomes. If no one is going to talk about this right now and it has to be me, then it has to be me," Fred Kane said.

He continued, saying he is done with the Wounded Warrior Project, except for his new mission of trying to see change there.

The board says it's ordered a review by independent auditors, and that it would be inappropriate to answer questions until all the facts are known.

Full disclosure, a CBS Corporate executive serves on that board. The board won't say if the results of their review will be made public, or whether the board's spending is under review as well. They have also hired legal counsel.