In what police say is an act of animal-rights protest vandalism, four severed animal heads were found in public locations in Tel Aviv Tuesday morning.

A sign decrying the killing of animals was attached to a cow head found on Ibn Gabirol street, and a sign on a sheep head found in a Jaffa public fountain read “The walls of the slaughterhouse have become transparent,” the police said. The fountain had been painted red, they added.

The police said that two additional heads, that of a goat and a sheep, were found Tuesday morning at Dizengoff Center and on Jerusalem Street in Jaffa, and are believed to be the work of the same culprits.

No group claimed responsibility for the acts as of publication. An investigation into the incidents has been launched, the police said.