## Facts

- Michael A. Sveum had a prior 1996 conviction involving stalking and harassment of his former girlfriend, Jamie Johnson, and later was released on supervision.
- In 2003, Johnson reported that Sveum was again stalking her.
- Police obtained a warrant authorizing installation and monitoring of a GPS device on Sveum’s car, including replacement as needed, with removal required as soon as practicable and no later than 60 days from the warrant date.
- Officers installed the GPS unit on the undercarriage of the car while it was parked in the driveway, without entering the vehicle or opening the hood.
- Police monitored the device for about 35 days, replacing it twice due to battery limitations, and then removed it.
- GPS data showed Sveum repeatedly drove near Johnson’s home and workplace.
- Using the GPS information, police obtained additional warrants to search Sveum’s residence and vehicle and recovered incriminating materials (including photos and logs).
- Sveum was charged and convicted of aggravated stalking; he moved to suppress GPS-derived evidence, and the motion was denied. The court of appeals affirmed.

## Issues

1. Whether installing a GPS device on Sveum’s car and electronically monitoring the car’s movements constituted a search or seizure under the Fourth Amendment and the Wisconsin Constitution.
2. If it did (or assuming it did), whether the warrant authorizing GPS installation and monitoring was valid and executed reasonably so that suppression was unwarranted.

## Decision

- The Wisconsin Supreme Court affirmed the conviction and the denial of suppression.
- Proceeding on the assumption that the GPS monitoring implicated Fourth Amendment protections, the court held the surveillance was supported by a valid warrant.
- The court held the warrant was sufficiently particular and not overbroad because it identified the specific vehicle, authorized only GPS placement and monitoring, and imposed a temporal limit.
- The court held execution was reasonable where officers stayed within the warrant’s scope, monitored for less than the authorized period, replaced the device only as needed, and did not intrude into the vehicle’s interior.
- Because the GPS evidence was obtained pursuant to a valid warrant and reasonable execution, suppression was denied.

## Legal Principles

- Even where technology-assisted tracking is treated as a Fourth Amendment search, evidence is admissible when the tracking is authorized by a warrant supported by probable cause and executed within its limits.
- A GPS-tracking warrant satisfies particularity when it specifies the object to be tracked (a particular vehicle), the method (GPS placement and monitoring), and a defined duration.
- Reasonableness of execution turns on compliance with the warrant’s scope and limits, including time restrictions and the manner of installation and monitoring.
- Suppression is not warranted when officers obtain and follow judicial authorization for GPS tracking and do not exceed what the warrant permits.

## Conclusion

The Wisconsin Supreme Court upheld GPS monitoring of a suspect’s vehicle where police secured a time-limited, vehicle-specific warrant supported by probable cause and executed it within authorized bounds, making the resulting evidence admissible in an aggravated stalking prosecution.


State v. Sveum, 787 N.W.2d 317 (Wis. 2010)