It was tire tracks in the snow at the scene of Jessica Lloyd's disappearance which led police to Colonel Russell Williams.
According to Globe and Mail sources, the distinctive tracks soon had detectives identifying the type of vehicle used in what appears to have been an abduction.
Last Thursday, on a stretch of rural highway, they set up the equivalent of a RIDE-program spot check, only this time they were looking not for drinking drivers, but certain vehicles.
Luck was on their side, because Col. Williams happened to be caught in the roadside check.
Larry Jones, a neighbour of Colonel Williams who was initially deemed a suspect in a pair of home invasions on their lakeside road, said it was the colonel's unique snow tires that caught the attention of police.
"Russ is pretty meticulous. When he buys a set of tires, he buys the best that's on the market. I guess they were a particular brand... they had a particular design on the tread," said Mr. Jones, who explained that he was told by police about the tire track link after he was cleared as a suspect.
"They looked at the tires on his truck, and took pictures of his tires ... took it back to the crime scene and matched the two."
The roadside discovery prompted police to sweep out across the province.
By Sunday, OPP officers with search warrants were combing through Col. Williams's cottage-like home on Cosy Cove Lane, and the residence he shares with his wife in the upscale Ottawa neighbourhood of Westboro.
It has been less than two months since the couple moved into the newly developed, $700,000 home on Edison Avenue. Col. Williams's wife, Mary Elizabeth Harriman, is the associate director of Canada's Heart and Stroke Foundation.
It was on Sunday afternoon that Col. Williams, a decorated pilot who has delivered prime ministers and soldiers to remote locales around the world, agreed to sit down with a behavioural science expert from the Ontario Provincial Police.
Investigators are saying nothing about what was discussed during those few hours.
But what has happened since that interview has shaken the Canadian Forces, and the citizens of three small towns in Eastern Ontario: Police charged Col. Williams, the commander of Canada's largest Air Force base, with the murder of two women, and assaults on two others.
And as quickly as the charges were laid against Col. Williams - he became the prime suspect in a string of unexplained attacks on women only five days ago - the detectives' net is widening even faster. Investigators are examining crime-scene evidence from several Eastern Ontario cities and additional charges are anticipated, sources familiar with the investigation said late last night. One officer close to the case said: "This may be all, but we suspect - a guy just doesn't start doing murders out of the blue."
Since September, detectives in three different communities near CFB Trenton have been searching for clues in what, on its face, appeared to be three separate incidents. In September, over a span of two weeks on a quiet lakeside road in the village of Tweed, two women living just a short walk from each other were tied up in the middle of the night and photographed by an unknown assailant.
Two months later, 78 kilometres west, in the town of Brighton, the boyfriend of CFB Trenton's Corporal Marie-France Comeau discovered his girlfriend dead in her home, the victim of what was quickly deemed a homicide.
Little more than a week ago, a Belleville woman, 27-year-old Jessica Lloyd, was reported missing when she failed to show up for her shift with Tri-Board Student Transportation in the town of Napanee.
Police found her body Monday morning.
During his brief appearance in a Belleville courtroom yesterday, Col. Williams loudly announced his name when asked, but quieted down when he answered that he understood the charges. For most of the proceeding, which is covered by a court-imposed publication ban, he stared down toward his feet. He wore a dark blue jumpsuit. Col. Williams has been relieved of his duties.
Ontario Provincial Police Detective Inspector Chris Nicholas confirmed at Tuesday's press conference that police will be exploring whether Col. Williams played any role in the 2001 unsolved murder and sexual assault near CFB Trenton of Kathleen MacVicar, 19.
For Det. Insp. Nicholas, the officer co-ordinating the expansive probe on behalf of the multiple police forces involved, the case is not his first involving a soldier alleged to have become unhinged.
In 1991, he arrested Stephane Menard, a former member of the disgraced Canadian Airborne Regiment, who was later convicted of murdering a Montreal cab driver.
With reports from Globe staff
Editor's note: An earlier version of this story mistakenly referred to Col. Williams as Col. Russell.