Pure Conspiracy theory, without anything to support the insinuation other than the GOP dreaded boogieman "Soros".
Soro's is a Billionaire, he probably has thousands of such investments in hundreds of different companies. It means ZILCH.
The only "proof" offered is that Embaer has been involved in corruption before. Yeah and corruption in the aircraft industry is obviously just a Brazilian problem. Its not like US aircraft companies would do that...Lockheed Martin in 1971 (Bribery scandal) and Boeing 2003 (inflating prices).
And of course one of the posters (WARLORD) stated this:
"I think we will find out that the USAF removed the AT-6 from the competition because the original RFP sought a “non-developmental” aircraft and the AT-6 (with only two prototypes in existence) is still very much in development".