D.C. police are looking for four persons of interest, shown in a surveillance video, who police say they believe were involved in a homicide that happened on the Fourth of July in Southeast Washington.The incident happened on the holiday around 11 p.m. in the 2600 block of Douglass Place SE. Police said 23-year-old Dwayne Gene Dillard died after he was shot in that area.In the video, which police released Monday, several men are seen walking down the street. In one instance, one man is seen sitting on the back of a vehicle and later he pulls a gun from his pants and begins to fire and run.