IOWA CITY — The FBI has identified an Iowa woman and her adult son as participants in the Jan. 6 riot at the U.S. Capitol after receiving a tip from a longtime family acquaintance, according to a court document unsealed Tuesday.Videos that Deborah Sandoval and Salvador Sandoval Jr. posted on social media and surveillance footage from the Capitol also confirmed they were part of the mob that illegally entered the building, an FBI agent wrote in an affidavit.Salvador Sandoval, 23, is also seen on surveillance video assaulting members of the Washington, D.C., Metropolitan Police Department, pushing two and trying to pry a shield away from a third, according to the document.The FBI announced last week that Deborah Sandoval, 54, and her son had been arrested on charges stemming from the attack.