The Justice Department is the latest government organization to launch an investigation into high-frequency trading.

While testifying before a House subcommittee group, U.S. Attorney General Eric Holder confirmed that the Justice Department is investigating high-frequency trading, a practice in which firms use algorithms and high-speed fiber optic lines to process trades.

"I can confirm that we at the Justice Department are investigating this practice to determine whether it violates insider trading laws," Holder said in prepared remarks. "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."

The Federal Bureau of Investigation (FBI) confirmed earlier this week that it is looking into the practice of high-frequency trading to determine whether traders are breaking the law by gaining access to non-public information. The Securities and Exchange Commission (SEC) had previously proposed regulations.

High-frequency trading has been around for years, but there has been renewed scrutiny of the practice this week due in large part to the release of a book from Michael Lewis, the prominent author behind works like Moneyball. The new book, called Flash Boys, was released on Monday and has already led to some heated exchanges among those in the industry on CNBC and Bloomberg.

"I think it's clear that HFT has a serious perception problem even if perception is worse than the reality. So I think these guys are responding to that," Charles Jones, a finance professor at Columbia Business School, told Mashable in an earlier interview. "Given the outcry and worry by some investors, it probably makes sense to look more closely and make sure there isn't any there there."

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