He was a sex predator who prowled Laval and other bedroom communities north of Montreal, preying on young women who walked alone at night.
Investigators only had the vaguest of descriptions to work with: a French-speaking white man in his 30s who wore a baseball cap.
The shocker came months later when the police announced the arrest of Constable Benoît Guay, badge number 4580, Service de police de la ville de Montréal.
It took a nine-month investigation to stop Constable Guay, and the story could not be told until yesterday, when the 36-year-old pleaded guilty to 13 counts of armed sexual assault and other crimes against eight girls and women. The eight were aged 15 to 20.
"It's important for these women that they weren't left behind. They have been recognized as victims," Crown prosecutor Isabelle Briand said yesterday.
It is a tale of how hard work and good luck enabled police to catch an unusual suspect.
But it is also a heartbreaking story. Despite having been spotted near the scene of his sexual assaults, Constable Guay wasn't immediately considered a suspect -- and attacked one more victim.
The attacks began in May of 2004, when a woman was stopped by a knife-wielding man who dragged her behind a bush to fondle her.
In the following months, the predator struck again and again. The modus operandi was the same, and the descriptions of the suspect were similar.
The attacks were also growing more violent, the suspect now making more explicit threats and using a pistol.
Two of the assaults took place near a service station in Laval, the last one in April, 2005.
Police reviewed the surveillance video from the gas station. It showed a red Honda Civic hatchback parked nearby. A bus arrived and several commuters got off, including the victim.
In the following days, Laval police handed a pamphlet to city bus drivers, urging them to look for a red Honda hatchback. Shortly before midnight on April 22, 2005, a bus driver reported she had seen a car matching the description near a shopping mall.
Two police patrollers stopped the driver. It was Constable Guay and he told them he had finished his shift and was waiting for a female friend.
"Benoît Guay was very curious about the reason why he was intercepted by the officers. He asked them the question three times in a short period," Detective-Sergeant Annie Pineault of the Sûreté du Québec testified at a bail hearing that was under publication ban until now.
Constable Guay worked for a squad doing undercover surveillance and had worked on cases against street gangs in Montreal.
He was now "a person of interest" to the investigation but not a suspect, Det. Sgt. Pineault testified.
It would be eight months before investigators met with Constable Guay. In between, a final victim was sodomized, the night of her 15th birthday.
At the same time, that assault would clinch the case against Constable Guay because it was the only one of the seven that yielded a DNA sample.
Det. Sgt. Pineault said investigators had to check 1,200 vehicles and question hundreds of people. "We had an enormous amount of information to verify," she told the court.
In mid-January, 2006, she visited Constable Guay and asked him about the night he was stopped near the gas station. "He was visibly nervous and stunned."
She told him 65 people had volunteered their DNA and asked him whether he would consent to give a blood sample. He flatly refused.
A few days later, Montreal police got a phone call from Constable Guay's brother, Robert.
He told them that he was worried about his brother, who was acting strangely and might be suicidal. "The past is catching up to me," he quoted Constable Guay as saying.
He said Benoît Guay told him he had three choices: "go into exile," "face the music" or "off myself."
"For us, it was the moment Benoît Guay became a suspect," Det. Sgt. Pineault said.
The next day, police obtained a warrant authorizing investigators to get DNA from him. He was taken to headquarters. As a blood sample was drawn, his face flushed, Det. Sgt. Pineault recalled.
The Laval predator had been caught.
Charges related to one of his seven victims were dropped, but Constable Guay -- who has now been stripped of his police badge -- confessed to two other previously unknown attacks, bringing his total number of victims to eight.
Ms. Briand, the Crown prosecutor, said she will seek to have the former officer labelled a long-term offender so he would face tighter surveillance after his eventual release from prison. Mr. Guay, whose wife is a Montreal police officer, faces a minimum four-year prison sentence for his crimes.
With a report from Ingrid Peritz in Montreal