Portland police say they’re stumped by a six-month spree of tire slashing and other vandalism that has damaged more than 500 vehicles. Damage is estimated at up to $250,000. The Oregonian reports that mostly, the damage is to tires, punctured by something like a tiny icepick. At first, many owners thought they had slow leaks — until they saw most of their neighbors had slow leaks, too. Police say they’re not sure whether it’s the work of one person, or a group.