But they may not have even done so. This is for alleged stalkers.
2km also essentially allows stalking them if you accuse them. Are they at home? Let's just walk within 2km and find out. Even just saying a distance and not location would make triangulation easy. Just go to 3 spots and see where the distances overlap. 2 would often be good enough for an educated guess.
I am more in favour of notifying police. 1km is probably still a bit of a wide area although if they are just notified first and only take action if you continue moving closer, say to 200m or so, then it might be more reasonable.