Thursday marks four months since a husband and wife were killed when they went for a walk near their home in Concord.Investigators said the bodies of Steven and Wendy Reid were discovered near the Marsh Loop Trail with multiple gunshot wounds.There have been no arrests or suspects named, but investigators released a sketch of a person of interest in May. A $50,000 reward is being offered for information leading to an arrest.Recent coverage:$50,000 reward offered for information in killings of Concord coupleObituary for slain Concord couple describes pair as perfect complements for each other Investigators: Owner of vehicle seen near Concord shooting not connected to caseSketch released of person of interest in shooting deaths of Concord couple Family of Concord couple in double homicide case thanks officials, describes how couple met Concord couple died of multiple gunshots; deaths ruled homicides, investigators say