Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. House Committee Chair Warns Trump Administration of Blocking Impeachment Probe VOA News U.S. House Intelligence Committee Chairman Adam Schiff warned Wednesday that Trump administration efforts to impede a congressional impeachment investigation into the president will be construed as proof of obstruction of justice. "We are concerned that the White House will attempt to stonewall our investigation," Schiff said during a news conference on Capitol Hill. "We want to make it abundantly clear that any effort by the Secretary [of State], by the president or anyone else, to interfere with the Congress' ability to call before it relevant witnesses will be considered as evidence of obstruction," Schiff added. .