A 23-year-old man walked up to a Harrisburg home, knocked on the door and gunned down the resident who lived there Saturday, police said in court documents filed Monday. Anthony K. Williams, 23, shot and killed Daniel Maldonado, 33, around 2:30 a.m. Saturday outside Maldonado’s home on the 400 block of Crescent Street in Harrisburg’s Allison Hill neighborhood, police said. Williams is also a Harrisburg resident, according to court records.