The House committee investigating the Jan. 6 assault at the U.S. Capitol is weighing whether to hire staff members who can analyze social media posts and examining the role foreign adversaries played in sowing divisions among Americans over the outcome of the presidential election, according to two people briefed on the committee’s decision making…

Witnesses this week included William J. Walker, the former commander of the D.C. National Guard, who has said military leaders delayed the guard response on Jan. 6, and the conservative activist Dustin Stockton, whose lawyer said he is turning over a “treasure trove” of documents that would have senior Trump allies and lawmakers “quivering in their boots.”

Mr. Stockton and his fiancée, Jennifer L. Lawrence, assisted in organizing rallies after the election advancing false claims about its outcome. But Mr. Stockton has said he was concerned that a march to the Capitol on Jan. 6 while Congress was certifying the election would mean “possible danger,” and that his urgent concerns were escalated to Mark Meadows, the White House chief of staff at the time, according to the committee.