BETHLEHEM, Pa. — I SPENT this semester teaching creative writing at Lehigh University. I’ve been a soldier, a police officer and an interrogator. So hearing students call me “Professor” and assigning homework was a significant change of pace.

But the course’s title, Writing War, kept me from straying too far from the memories that have haunted me over the last decade. I am grateful to Lehigh for the opportunity to teach the course. The school’s willingness to put a veteran in the classroom is the very thing this country needs to be doing in order to collectively process what the last 13 years of war have wrought. But teaching a class about war reminded me daily that I am no college professor.

I was an interrogator at Abu Ghraib. I tortured.

Abu Ghraib dominates every minute of every day for me. In early 2004, workers inside Abu Ghraib were scrambling to cover the murals of Saddam Hussein with a coat of yellowish paint. I accidentally leaned up against one of those walls. I still wear the black fleece jacket with the faded stain. I still smell the paint. I still hear the sounds. I still see the men we called detainees.

Last month, my students at Lehigh read “The Things They Carried” by Tim O’Brien. During class I talked about the things American soldiers carried in Iraq. I brought in a cigar box filled with the trinkets and mementos I had purchased from Iraqi vendors at Baghdad International Airport. I brought along the black fleece jacket.