North Carolina's Supreme Court is re-evaluating whether forcing sex offenders to be perpetually tracked by GPS-linked devices, sometimes for the rest of their lives, is justified or a Constitution-violating unreasonable search.

The state's highest court next month takes up the case of repeat sex offender Torrey Grady. It comes three years after the U.S. Supreme Court ruled in his case that mandating GPS ankle monitors for ex-cons is a serious privacy concern.

"There's different possible outcomes of the case. One is that it's never reasonable at all. Another is that it's reasonable, maybe while the person is still on post-release supervision" for five years after prison release, said James Markham, a professor who focuses on criminal law at the University of North Carolina's School of Government. "Another possibility is that it's reasonable for the rest of their life."

Grady took his case to the nation's top court arguing that having his movements forever monitored violated his constitutional protection against unreasonable searches. The U.S. Supreme Court ruled that attaching a device to a person's body in order to track their movements qualifies as a "search" and a question of constitutional rights. But the decision left it up to states to decide whether imposed monitoring is reasonable, and for how long.