Senator Charles Grassley, the crotchety, plain-speaking Republican from Iowa, has been trying for a couple of years to pry open the books of televangelists he suspects of living decidedly unhumble lives on the donations they receive. He questions whether they deserve the tax exemption they enjoy. A recent report that Inspiration Network's CEO David Cerullo spent around $4 million on his new mansion could provide more fuel for this smoldering investigation.

Cerullo's new 9,000 square-foot home and 2,000 square-foot porch overlook Lake Keowee. Meanwhile, Inspiration and its subsidiaries have laid off a number of workers, frozen wages, stopped 401K contributions, and turned the thermostat in its headquarters down to 65 degrees last winter.

According to the Charlotte Observer, Cerullo's network will bring in close to $100 million this year, much of it donations. It has also received up to $26 million in incentives over the past few years from the state of South Carolina. These were given to lure the network from its former home in Charlotte. Cerullo receives over $1.5 million a year in salary.

Grassley launched an investigation of six noted televangelists in 2007, challenging them to defend their expenditures and justify their tax exemptions. Included were the ministries of Paula White, Joyce Meyer, Creflo Dollar, Eddie Long, Kenneth Copeland and Benny Hinn. Several have cooperated fully, a couple partially. Creflo Dollar continue to hold out. Kenneth Copeland Ministries pulled a clever dodge, offering to cooperate with the IRS should it choose to investigate the ministry. IRS investigations are not made public.

Grassley points to the tax code language prohibiting not-for-profit organizations from paying unreasonable compensation to the executives. What is reasonable, he asks? In this case, I think the people to answer that question are those who donated to the Inspiration Network. Are you content that some of your money went for a $4 million home for Cerullo?