Police in Upper St. Clair sent out an alert to residents, warning them about a recent vandalism spree that began when school was let out in June and has progressively gotten worse.
Investigators said the vandals are targeting not only homes, but churches and cars as well.
On Wednesday, police sent an automated phone call to residents with a recorded message saying, "This is the USC Police Department with an important message. A rash of criminal mischief has spread across the township this summer and it has grown increasingly malicious."
Police said they've had numerous reports of damage including slashed tires, smashed windows, destroyed mailboxes and damage to outdoor decorations.
More recently, police said the vandals used a hatchet to damage a garage door. The homeowner said it will cost about $1,000 to repair.
A rock was also thrown through a stained-glass window at St. Gregory Catholic Church.
Investigators said the hatchet and church incidents happened sometime between 1 p.m. Tuesday to 3 a.m. Wednesday.
Police ask anyone who sees suspicious activity to report it to police immediately.