State v. Jackson
In State v. Jackson (2003) 150 Wn.2d 251, the defendant was suspected of involvement in his young daughter's disappearance.
Local police obtained two 10-day warrants allowing them to attach GPS devices to the defendant's vehicles. GPS monitoring data showed that defendant had traveled twice to a remote site, where the girl's body was later discovered in a shallow grave. (Jackson, supra, 150 Wn.2d at p. 257.)
In evaluating the defendant's challenge to the GPS warrants on state constitutional grounds, the Washington Supreme Court ruled that "installation and use of a GPS device on a private vehicle involves a search and seizure under article I, section 7 of the Washington State Constitution," and that a warrant is therefore required. (Id. at p. 264.)
The basis for the ruling was the court's determination that "use of GPS tracking devices is a particularly intrusive method of surveillance, making it possible to acquire an enormous amount of personal information about the citizen under circumstances where the individual is unaware that every single vehicle trip taken and duration of every stop may be recorded by the government." (Ibid.)
The court rejected the view that "use of the GPS devices to monitor the defendant's travels merely equates to following him on public roads where he has voluntarily exposed himself to public view." (Id. at p. 261.)