The evidence was in the garbage, and only the last two weeks of garbage still was at the facility, so the police were able to find evidence only for the ten people she had poisoned in the last two weeks, but it is believed that there were many more victims.
It is unacceptable for patient safety measures to be established on the assumption that medicine is full of good people who want to do the right thing.
Her nursing license eventually was revoked. She is serving life in prison.