Justice Department probing high-speed trading, Holder says

Attorney General Eric Holder announced Friday that his Justice Department is investigating the practice of high-speed trading to see whether insider trading laws were violated. 

This comes after the FBI and federal regulators said they were looking into potential wrongdoing. 

"The Department is committed to ensuring the integrity of our financial markets -- and we are determined to follow this investigation wherever the facts and the law may lead," Holder said in written testimony before a House committee.