The nomination of Minnesota U.S. Attorney B. Todd Jones to head the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) is running into stiffening GOP resistance in the Senate. Republicans on the Senate Judiciary Committee requested Tuesday that top federal law enforcement officials in Washington turn over documents that might reveal "conflicts" with Jones, President Obama's pick to become the permanent head of ATF, a position he now holds on an interim basis. The requests were made in a series of letters from Iowa Sen. Charles Grassley, the ranking Republican on the committee, to the heads of the FBI, DEA, and U.S. Immigration and Customs Enforcement (ICE). Jones had no comment on the request, according to a spokeswoman for the U.S. Attorney's office. No date has been set for a vote on his nomination, which the White House announced in January. The letters, obtained by the Star Tribune, allude to three unnamed witnesses, presumably all law enforcement officials in Minnesota, who reportedly talked privately to Grassley's staff. Sources close to the matter say they are afraid to come forward for fear of retaliation. Nevertheless, Grassley cited them to contradict Jones' testimony before the Senate last month that he was unaware of any "deterioration" in relations between his office and law enforcement agencies in Minnesota. The letters also refer indirectly to a whistleblower complaint brought against Jones by Jeffrey Paulsen, an assistant U.S. attorney in Minneapolis, who says he was unfairly disciplined by Jones for raising management concerns. According to Grassley's letters, his staff also talked by telephone last week with Donald Oswald, the former head of the FBI office in Minneapolis, who said that he had "personally" talked to Jones about complaints against his office. In his June 11 appearance before the Judiciary Committee, Jones said he had been "surprised" by a letter Oswald had submitted previously to the Senate saying that Jones had an "atrocious professional reputation" in Minnesota. Oswald's judgment of Jones' was sharply disputed by Bush-era U.S. Attorney Tom Heffelfinger, who suggested that Oswald, who has since moved to Florida, was not in Minnesota long enough to assess Jones' reputation. In reply to an previous follow-up question from Grassley, Jones pointed out that his nomination has been backed by public letters of support from numerous leaders in Minnesota law enforcement, including Heffelfinger and Minnesota Bureau of Criminal Apprehension (BCA) agent Michael Campion, who was former Gov. Tim Pawlenty's public safety commissioner. Minnesota Democrats Amy Klobuchar and Al Franken, both members of the Senate Judiciary panel, have lined up in support of Jones. Grassley's three nearly-identical letters are addressed to FBI Director Robert Mueller, ICE Director John Morton, and DEA Administrator Michele Leonhart, a St. Paul native who once worked out of the Twin Cities' DEA office. All three are being asked to turn over any communications they have suggesting "conflicts" and "expressions of dissatisfaction" with Jones and others in the U.S. Attorney's Office in Minnesota over what cases to prosecute. Grassley has also requested that the FBI make available the head of the Minneapolis FBI office, J. Chris Warrener, and former acting head Richard Thornton.