DANBURY — One year after a 23-year-old Bethel mother was killed in a hit-and-run accident, her friends and family are still looking for closure. Police have made no arrests in the case, but have identified a vehicle of interest, which is described as a white van with a ladder rack and passenger-side windows. Friends and family have described her as an athletic, kind and compassionate person. Gerard Sack urges Danbury-area residents to try to remember any suspicious behavior by someone owning a white van in the days following the accident, which happened a week after Halloween. “If they noticed somebody trying to change the appearance of their van, maybe removing the ladder rack, changing the color, maybe keeping it in the garage, which they never did for long periods of time,” he said. “While we don’t think there’s anything imminent, we certainly hope we’ll be able to arrest the individual or individuals responsible for this,” he said.