Chicago, IL: Police vehicles sabotaged, anarchist symbol left nearby

from the press:
A vandal or vandals have been at work at a Morgan Park neighborhood police station, loosening lugnuts on squad cars there and plunking a large piece of concrete spray-painted with an anarchy symbol in the station parking lot.
“It weighs every bit of 50 pounds,” said a Morgan Park District officer. “It’s a big hunk of concrete found in the middle of the parking lot.”
An officer discovered it Thursday morning at the station, 1900 W. Monterey Ave. on the Far South Side, and it was blocking some lanes of the lot. A white spray-painted “anarchy A” symbol was found on each side of the concrete block, which is about 15 inches by 15 inches and 8 inches thick, said the officer.
Authorities have no idea who placed it there. Officers carried it into the station, inventoried the concrete and developed a police report on the incident, the officer said.
And that’s not all, the officer reported.
“We’ve come across four cars with lug nuts either removed or loosened,” in the lot, said the officer, who said the latest was discovered today.
“The first one was last week and then there’s been two or three more – today and yesterday,” according to the officer, who said it could be extremely dangerous and cause a wheel to fall off.
The Morgan Park District Commander yesterday ordered a check on all their squad cars, the officer said. No arrests have been made and the boulder did not cause any damage.
A video camera is set up at the lot, but because of newly bloomed leaves, its view is obstructed. So police stationed one officer to watch the lot, the officer said.