The McHenry County Health Department announced Friday morning that it is investigating a common source of exposure among six of 12 McHenry County patients diagnosed with Legionnaire's Disease in June. During the investigation, three new cases were found, adding to the nine announced previously. Those previous nine cases ranged in age from 46 to 82 years old. Working closely with the Illinois Department of Public Health and the Centers for Disease Control and Prevention, the MCHD determined that six patients either lived, worked or spent time within a mile and a half radius around the intersection of Route 176 and Walkup Road in Crystal Lake. The other six patients' activity was not connected.