A man wanted for gunning down a woman last month in Ocean County fatally shot himself Friday evening following a nearly seven-hour standoff with police in a Toms River neighborhood, investigators said. Maxwell Johnston, 35, of Manchester Township, died from a self-inflicted gunshot wound in a home on Ravenwood Drive in Toms River, according to a statement from Ocean County Prosecutor’s Office. Johnston was wanted in connection with the June 27 killing of Gabriella Caroleo, a 25-year-old Seaside Heights woman who was shot in Manchester Township, police said. “We thank everyone in the neighborho…