Conversation so far:
What was the detection of Harold Shipman?
Harold Shipman was detected when concerns were raised about the high death rate among Shipman's patients.
Are there any other interesting aspects about this article, besides the detection of Harold Shipman?
In particular, she was concerned about the large number of cremation forms for elderly women that he had needed countersigned
What was Harold Shipman being investigated for?
Harold Shipman was being investigated for murder
How did Harold Shipman kill them?
Shipman killed his victims by administering lethal doses of diamorphine (heroin), signing patients' death certificates, and then falsifying medical records to indicate that they had been in poor health
When was Harold Shipman caught?
Shipman was arrested on 7 September 1998
How did the police catch Harold Shipman?
Police exhumed a body, found traces of diamorphine, and found Shipman falsified medical records and a newly-written last will and testament that awarded Shipman money
Was Harold Shipman a serial killer?
Yes, Harold Shipman was one of the most prolific serial killers of all time, at an estimated 250 deaths
Who were some of Harold Shipman's other victims?
He was charged with the murders of Marie West, Irene Turner, Lizzie Adams, Jean Lilley, Ivy Lomas, Muriel Grimshaw, Maureen Ward, Winifred Mellor, Joan Melia and Kathleen Grundy, and more

Question: How did he kill them?
Self-contained rewrite: How did Harold Shipman kill them?