By Jay Gormley, CBS 11 News

DALLAS (CBSDFW.COM) – An 18-thousand square foot home valued at $6.3 million.  A fleet of airplanes, including private jets.

Those are just some of the reasons that Senator Chuck Grassley of Iowa launched an investigation three years ago into Kenneth Copeland Ministries based in northwest Tarrant County.

The findings were released Thursday.  Click here to read the full report.

Copeland Ministries was one of six ministries investigated starting in 2007.  Senator Grassley wanted to know if six high-profile TV evangelists were using church donations to live lavish lifestyles.

While the Copelands declined comment Thursday, Kenneth’s son and CEO John Copeland sat down with CBS 11 for an interview in June of 2008 to address the investigation.

“There’s a lot of doctrine that teaches that you’re not a good Christian unless you’re poor.  But that’s not our doctrine.  That’s not what we believe.”

Copeland Ministries preach what’s called the prosperity gospel; the belief that God rewards the faithful both spiritually and financially.  John Copeland told us in 2008 that it takes a private jet and lot of money to spread that message.

“A lot of people may see that as a luxurious lifestyle, but when you hit 19 countries in 12 months, what are you going do that with.”

Benny Hinn’s World Healing Center church, based in Grapevine, was also investigated.  According to Senator Grassley, Hinn cooperated and promised internal reforms.

But Copeland Ministries offered little cooperation. In Grassley’s report, a former employee stated: “the Copelands employ guerrilla tactics to keep their employees silent. We are flat out told and threatened that if we talk, god will blight our finances, strike our families down and pretty much afflict us with everything evil and unholy.”

In June of 2008 John Copeland called the senator’s request for full financial disclosure violated the separation of church and state.

“Now if we give up that right, then we’re giving up that right for every church in America. If we set presidency here, then what happens when the next senator has a problem with somebody’s doctrine over here.”

The investigation questions the millions of dollars brought in each year by Copeland Ministries.  It also raises concerns that the Copelands may be using their private jet, which is paid for by donations, for more than just spreading the gospel.

A former employee stated the jet has been used for hunting trips, shopping excursions, routine medical visits and vacations in other states.

Senator Grassley’s office tells CBS 11 that the investigation was to provide evidence to congress for possible changes in the tax laws for television ministries. As of now, none of the ministries face any punishment.