Lake Hefner is a peaceful, outdoor recreation area in northwestern Oklahoma City with 17 miles of shoreline. It’s a place where families go to get away from city life and enjoy some genuine interaction with nature and visit local shops and restaurants.

It was a warm evening in late May and hungry patrons packed the dining area at Louie’s On The Lake, a local bar and grill. Unbeknownst to those present, a crazed man had hidden himself among the trees near the restaurant. As...