 After the 1982 Tylenol murders , FDA regulations went into effect which made it a federal - rather than just a state or local - crime to tamper with consumer products . Local and state authorities are not , however , prevented from also filing charges in such cases . Under this law , Nickell 's crime was prosecutable as a federal product tampering case as well as a state murder case , and she was convicted not of murder , but of product tampering that caused death . The possibility of state charges for the actual murders of Susan Snow and Bruce Nickell continues to exist . 
