BEAUFORT COUNTY, S.C. (WSAV) - The Beaufort County Sheriff's Office (BCSO) has arrested a fourth individual in connection with the September 15 murder of a 17-year-old girl. According to the Beaufort County Detention Center, Derrick Jerrod McKee, 17, of Beaufort, has been charged with murder, aggravated breach of peace and possession of a weapon during a violent crime. Jeremiah Warren, 18, and Rashod Lorenzo Williams, 18, both from the Beaufort area along with Storm Lemont Zop Polite, 23, of Dale, were previously arrested on the same charges following the September incident. The four are accused in the murder of 17-year-old Ari’Anna Mulligan. Mulligan had previously attended Whale Branch College Early High School but transferred to Bridges Preparatory School, where she had just started her senior year at the time of her death. The investigation into this incident is ongoing. Anyone with information is asked to contact Master Sergeant Duncan at 843-255-3418. Information can also be submitted online at BCSO.NET.