The American Civil Liberties Union (ACLU) has sided with a suspected Minnesota deer poacher who is fighting the Department of Natural Resources over a bust made possible by a hidden tracking device.

“The outcome of this case will have a significant impact on the rights of other Minnesotans who may be the subject of warrantless GPS tracking,” the ACLU wrote to the Minnesota Court of Appeals. The organization is asking for legal standing to join the case as a “friend of the court.”

The ACLU’s involvement raises the profile of the already closely watched criminal prosecution of Joshua Liebl for alleged game violations in Lac qui Parle County. The DNR arrested him in fall 2014 after agents attached a GPS tracking device to the underside of Liebl’s pickup truck. They caught him with a dead buck that he allegedly shot with a gun during bow hunting season. Agents went on to seize a large number of deer mounts, guns, a frozen piebald deer and other items from Liebl’s home in Dawson.

Last month, District Judge Thomas Van Hon dismissed 13 charges against Liebl, saying the DNR did not obtain a search warrant. The DNR recently appealed the decision, saying a court-approved tracking order was sufficient legal grounds for the surveillance.

Liebl’s attorney, Bill Peterson of Bloomington, welcomed the ACLU’s participation as validation that important constitutional privacy rights are at stake. Peterson, the ACLU and the DNR all have until July to make their arguments in writing. A decision is expected before the end of the year.