A PADDED envelope delivered to Bridlington police station containing a suicide note and a key to the home Sybil and John Appelquist shared on West Hill estate was to prompt the search for Sybil.
The note, sent in November 2002, was from John Appelquist.
Officers found him at the house in Cranbeck Close. He had slashed both his wrists and was in a serious condition.
He told them his wife had left him, and was taken to hospital in Scarborough where he was to remain for several weeks.
From that point on police launched a missing persons inquiry which was to become one of the biggest and most detailed investigations the force had undertaken.
It would lead to the conclusion that Sybil had “ceased to exist” and could have been missing for up to a year.
In a joint campaign with police the Free Press flooded the town with more than 200 posters of Sybil asking the public to contact police if they knew where she was. There was also regional press and radio and TV publicity.
The missing person’s inquiry was stepped up.
In February 2003 the house in which the former Hilderthorpe and Headlands school girl was born and brought up with her brother Anthony by their parents Sybil and George Hornby, was the scene of intense activity in an attempt to find any clue as to where Sybil had gone.
She had vanished without taking any personal possessions including her passport or money.
The garden was dug up, a nearby lock-up garage searched.
When contacted by the police, her brother Anthony who had been living in London since 1985 had no idea she was missing and said he had last spoken to her on the phone in March 2002.
He described her disappearance as “completely out of character.”
Her sister-in-law Pam Appelquist of Arnold‘s Fisheries in Queen Street where Sybil had worked for 12 years, had not spoken to her for a while and was also unaware she was missing.
There were no other near relatives and the couple did not have children, and few friends.
The house in Cranbeck Close was scoured for clues and minutely examined.
At the time Detective Chief Inspector Bill Sparnon who was leading the inquiry said he “feared the worst” and could find no indication Sybil was alive and well. “Almost everything of hers including clothing and jewellery has gone from the house. It is as though she never lived here,” he said.
As lines of inquiry not just in Humberside but elsewhere in the country continued, police were starting to build a detailed picture of Sybil’s past, her every day life, every conceivable source of information was checked out.
Hospitals, women’s refuges, car boot sales she was known to have frequented, even institutions for the mentally ill (Sybil was known to suffer from bouts of depression) ports and airports, banks, doctors, dentists, lists of benefits claimants, anything that could indicate she was alive and living a new life somewhere else.
They all drew a blank and as each day went by they became more convinced she was dead, but had no idea how she died or where her body could be.
A major incident room had been set up in Driffield with more than a dozen detectives working on her disappearance and dealing with a vast amount of data and information about her life.
They stressed it was a missing persons inquiry but in February 2003 John Appelquist was arrested on suspicion of murdering his wife .