INDIANAPOLIS (AP) — The president of the Indiana NAACP has accused detectives of covering up the bungling of the investigation into a northern Indiana house fire that killed four sisters — a charge vehemently denied by the Indiana State Police chief.

The NAACP's Barbara Bolling-Williams said Thursday the lack of progress into the Nov. 21, 2016, fire in Flora "smells of a cover-up" and questioned what she called a "silence" surrounding the case.

The fire that investigators deemed arson killed 11-year-old Keyana Davis, 9-year-old Keyara Phillips, 7-year-old Kerriele McDonald and 5-year-old Konnie Welch and injured their mother and two others.

ISP Superintendent Doug Carter said at a news conference the charge of a cover-up was unsubstantiated and "strikes me at the very core of who I am and the industry that I represent."