Did the FBI raid Jefferson's office and seize evidence to protect Cheney?

I have my suspicions as to why the FBI targeted Representative Jefferson's office to raid and yet never raided and siezed documents from Tom Delay's office, or Duke Cunningham's office. However, there may be a more sinister reason as suggested by the Wayne Madsen Report:

Nigerian connections to political bribes ultimately linked to U.S. oil industry. According to informed sources, the $90,000 found in Louisiana Rep. William Jefferson's freezer by the FBI had its origins with Nigerian politicians who include two 2007 presidential hopefuls, current Vice President Atiku Abubakar and former President Gen. Mohammadu Buhari, as well as former Nigerian President Gen. Ibrahim Babangida.

The Nigerian Economic and Financial Crimes Commission (EFCC) is looking at the three politicians and evidence that they have been used by foreign oil companies to launder money into the coffers of Nigerian and foreign politicians, including Jefferson. The Louisiana congressman is being investigated for receiving over a half million dollars in bribes from iGate, Inc., a Louisville, Kentucky-based company that was using Jefferson to promote its Internet and wireless business in Nigeria, Ghana, and Cameroon. In the case of Nigeria.

Jefferson allegedly attempted to double dip by receiving a finder's fee from iGate for an introduction to Nigerian political leaders and company officials of Nigeria's Netlink Digital Television of Nigeria and also receive direct sales commissions from Netlink. Netlink's lawyers blew the whistle on Jefferson's illegal gambit.

The Nigerian bribery scandal involving Jefferson is also linked to previous bribes paid to Nigerian politicians by U.S. oil companies, including $180 million in bribes paid by Halliburton, while Dick Cheney was its chairman, to Nigerian officials in return for a gas liquefaction plant contract in Nigeria.

The FBI's raid on Jefferson's office may have had more to do with eliminating evidence involving U.S. oil companies in Nigerian bribery schemes (and, therefore, protect Cheney) than in nailing Jefferson. >>>More