The House committee examining the Jan. 6 attack disclosed on Tuesday that it had interviewed the man at the center of a right-wing conspiracy theory about who provoked the violence, noting that he had denied reports he urged protesters into the Capitol at the behest of federal law enforcement agencies. The committee said its investigators spoke in November with the man, Ray Epps, who was seen on video urging people to march into the Capitol. Some Republican members of Congress and other supporters of former President Donald J. Trump have promoted a theory that Mr. Epps was working for the...