PIERCE COUNTY, WIS. — A roofer used a circular saw to kill a co-worker Monday, police said. Maguel A. Nabarro, 24, used the saw and cut Israel Valles-Flores, 37, severely on the neck and face, according to WQOW. Police found Valles-Flores unconscious on a roof where the men were working around 4:30 p.m., the St. Paul Pioneer Press reported. Nabarro, of St. Louis, was arrested and charged with suspicion of intentional homicide, the Pioneer Press reported.