The officer, Michael Fanone, who joined the force after the Sept. 11, 2001, attacks and has been on leave since the riot, wrote of his misgivings in a letter he said he sent on Wednesday to members of Congress, the D.C. Council and the mayor’s office. He wrote he has “struggled with many aspects of that day,” and said that as his physical injuries from being dragged into a crowd, beaten and attacked with a stun gun subsided, he began to feel “psychological trauma.” Added to that, the 40-year-old officer wrote, is the “emotional anxiety” he said he feels when people deny that the insurrection that left one Capitol Police officer and four others dead was violent. “The fighting here was nothing short of brutal,” Fanone wrote in the letter. “I observed approximately thirty police officers standing shoulder-to-shoulder maybe four or five abreast using the weight of their own bodies to hold back the onslaught of violent attackers.”