Conversation so far:
What was detection?
CANNOTANSWER.
Are there any other interesting aspects about this article?
case.
Between 17 April 1998, when the police abandoned the investigation, and Shipman's eventual arrest.
What was he being investigated for?
he killed three more people.
His last victim was Kathleen Grundy, who was found dead.
How did he kill them?
the last person to see her alive and later signed her death certificate, recording "old age" as the cause of death.
When was he caught?
September 1998.

Question: How did the police catch him?
Self-contained rewrite: How did the police catch Shipman?