Complex sentence: Riddick recruited participants from all sectors of Durham, and invited Atwater to co-lead the charrette with C. P. Ellis, the Exalted Grand Cyclops of the Durham Ku Klux Klan at the time.
Split into simpler sentences: Riddick recruited participants from all sectors of Durham, and invited Atwater to co-lead the charrette with C.P. Ellis. Ellis was the Exalted Grand Cyclops of the Durham KKK at the time.