The first three cases occurred within 15 days in February 1991; the fourth incident occurred in March after an announced recall of Sudafed capsules and amid the publicity surrounding the first three cases. This article describes the details of these cases including the chronology, causes of death, autopsy, and toxicological findings. During the investigation, police found six packages of Sudafed laced with sodium cyanide either on supermarket shelves or in home medicine cabinets; all the packets were within the Tacoma and Olympia region. Each tampered packet contained only one poisoned capsule; the only obvious evidence of tampering was the mismatched blister pack and box lot numbers. 1 table and 9 references