Dale Cregan has pleaded guilty to the murder of former Island resident Fiona Bone and her colleague Nicola Hughes.
Police constables Bone and Hughes were shot in Tameside in Greater Manchester last September as they responded to a report of a burglary.
Twenty-nine-year-old Cregan has this afternoon changed his plea, and admitted killing them.
Thirty-two-year-old Miss Bone, whose parents live in Port St Mary, was a former Castle Rushen High School student.
Cregan remains on trial for the murders of a Manchester father and son.
There are also nine co-accused whose charges include murder and attempted murder.