In the first case, authorities say people are grabbing baseball-sized rocks from spill-wells and smashing them through cars and mailboxes.
The vandalism was reported in several towns in the western part of Berks County over the weekend.
Police don't believe this is connected to a recent tire slashing case, in Spring Township, Berks County.
In that case police say someone damaged at least ten vehicles parked at the Berkshire Hills Complex over the weekend.
Damage is estimated at $2,000.
