A group of congressional lawmakers has asked the Justice Department for answers on a secretive unit inside the U.S. Drug Enforcement Administration that has used information taken from NSA wiretaps for cases unrelated to terrorism. Earlier this month, Reuters revealed the DEA’s Special Operations Division funnels information from overseas NSA intercepts, domestic wiretaps and informants to help DEA agents launch criminal investigations of Americans. DEA agents are then instructed to recreate the investigative trail in order to conceal the origins of the evidence. The DEA has also provided classified intelligence obtained by the NSA and other sources to the Internal Revenue Service to help in their investigations of Americans. On Monday, eight Democratic congressmembers asked Attorney General Eric Holder to answer questions about the unit’s operations. In a letter to Holder, the lawmakers said: “These allegations raise serious concerns that gaps in the policy and law are allowing overreach by the federal government’s intelligence gathering apparatus.” Congressional aides say the issue will be discussed in classified briefings next month.