King County Sheriff McGraw and King County Coroner L. B. Dawson conducted an investigation of the shooting the next day. The coroner convened an official inquest to look into the matter, and on Tuesday, September 8, a hearing was held. At the hearing, eleven men testified before a jury of six local residents. Those testifying were: Gong Heng, Joseph Day, I. A. Wold, L. A. Wold, Sam Gustin, M. De Witt Rumsey, J. A. Wold, George W. Tibbetts, William A. Wolf, Perry Bayne, and Sam Robertson. Under oath, Robertson admitted taking part in the shooting and named several others who were there with him. The jury found that the Chinese were killed "by gun and pistol wounds initiated by M. DeWitt Rumsey, Joseph Day, Perry Bayne, David Hughes, Samuel Robertson, Indian Curley, Indian Johnny and other persons to us unknown."