the investigation in Walkerton. The MOE environmental officer dispatched by Bye, John Earl, spoke first to David Patterson (the Assistant Director of Health Protection at BGOSHU), who expressed his growing suspicion that Walkerton PUC water was the source of the contamination; Patterson asked Earl to obtain further information and records from Stan Koebel, the PUC manager. Koebel, in his verbal interview with Earl, failed again to provide information about adverse water testing results and other potentially crucial system information; he informed Earl that Well 7 has had a new chlorinator installed, for example, but omitted mention that this had been after the well had pumped unchlorinated water into the system for days. Earl requested and was given documentation regarding well testing, water distribution maps, and pumping history for the wells. Included in this documentation were records of the May 17 adverse testing results of May 15 samples from the "Highway 9" water main construction; excluded was pumping history for Well 7. Earl returned to the MOE with these documents and reviewed them, noting the May 17 testing results, but notified no one else of these results. After Earl left the PUC, Stan Koebel contacted his brother Frank to ask him to "clean up" the pumping log for Well 7. Stan Koebel hoped to have a new document to present to Earl the next day that would not reflect that Well 7 had been unattended to and unchlorinated. Frank Koebel complied with this request. He destroyed the previous version of the document and created a new one with fictitious data: the new document showed Well 7 as not having operated on the days it had actually been pumping unchlorinated water into the system, and contained chlorine residual records for Well 7 which were entirely fictitious. Frank Koebel later testified that he had falsified this document "so it would look better to the MOE". While the Ministry of the Environment investigated the outbreak from the procedural end, public health officials swung into a medical investigation. Early epidemiological investigation had demonstrated fairly strongly that infection risk seemed to correlate to physical presence in Walkerton—even for patients visiting other area hospitals, investigators typically found that the patient lived in or had visited Walkerton during the period of their infection— and investigators now began making telephone calls to patients, gathering information about onset of symptoms, possible methods of exposure, and the patients' personal demographic information.