Gary Ridgway made frequent trips to Vancouver in western Canada during his admitted murder spree that began two decades ago, according to police investigating the murder of prostitutes in the city.
“Mr Ridgway has not been ruled out as a suspect in our cases up here,” the police spokeswoman said.
“I would anticipate that our investigators will probably have further discussions with those investigators in Washington state at some point in the future.”
Ridgway has pleaded guilty to 48 charges of premeditated aggravated murder under a deal with prosecutors that will spare him the death penalty
“I wanted to kill as many women as I thought were prostitutes as I possibly could,” Ridgway said in a statement read out by prosecutors.
“I killed so many women I have a hard time keeping them straight.”
However the 54 year-old has struck a plea bargain that will spare him from the death penalty and result in a sentence of life in prison without parole.
The agreement will put more murders on his record than any other serial killer in US history.
The Green River Killer’s murderous frenzy began in 1982, targeting mainly runaways and prostitutes in the Seattle area. The first victims turned up in the Green River, giving the killer his name. Other bodies were found near ravines, airports and freeways.
In court, Ridgway said he killed all the women in King County, mostly near his home or in his truck not far from where he picked them up.
He said he had several reasons for preying on prostitutes.
“I hate most prostitutes and I did not want to pay them for sex,” he said.
“I also picked prostitutes as victims because they were easy to pick up without being noticed. I knew they would not be reported missing right away and might never be reported missing. I picked prostitutes because I thought I could kill as many of them as I wanted without getting caught.”
Ridgway was arrested in 2001 after prosecutors matched a DNA sample from him with other samples taken from the bodies of three of the earliest victims.
Ridgway had been a suspect as early as 1984, and he even contacted the King County sheriff’s Green River task force – ostensibly to offer information about the case – and passed a polygraph test.