Some banks may be manipulating prices in Fannie Mae and Freddie Mac unsecured debt, according to several investigations launched late last week.The Department of Justice has reportedly opened a criminal investigation while the law firm of Hagens Berman is investigating the potential fraud.They suspect that traders from several banks have engaged in a coordinated attempt to manipulate pricing. Hagens Berman attorneys encourage investors and whistleblowers to report any information about potential antitrust violations and other fraud in the bond trading market to a tip line they recently established. This type of fraud has a large impact on market participants, according to Steve Berman, managing partner of Hagens Berman.