DETROIT -

A 15-page FBI search and seizure warrant claims Dr. Farid Fata performed medically unnecessary cancer treatments and directed his staff to lie to patients and insurance companies to justify the spending.

The FBI believes emails to workers, drug companies and financial advisors will prove how Dr. Fata committed health care fraud.

The 19-page affidavit included several emails. In one from July 2012, Dr. Fata wrote to a drug manufacturer after they denied a grant to his charity "Swan For Life." In it he wrote: "I expect further support form AMAG, Please proceed ASAP. I will be happy to talk to Dr. XXXXXX to reconsider IF ANYBODY DESERVES SUPPORT IT IS US! i.e. SFLCF Please advise, Dr. Fata."

The FBI says the drug manufacturer was told to donate $10,000 to the charity or Dr. Fata would stop ordering the drug.

With tens of millions of dollars coming in, the FBI says Fata was looking at where to invest, including luxury properties overseas.

In August 2010, Dr. Fata wrote to a business associate: "I need a favor from you. My dad has a great deal on a castle all furnished in Adma/Lebanon! Can you pls get in contact with my dad and go see the house! It is for $3,000,000 ... "

Fata is in jail on a $9 million bond and faces 11 civil suits.

SPECIAL COVERAGE: Cancer doctor's fraud case