Someone left a severed pig's head at this Philadelphia mosque

In the early hours of Monday morning, a caretaker at the Al Aqsa Islamic Society, a mosque in northern Philadelphia, found a severed pig’s head on the doorstep. A pig’s head is especially offensive because Muslims, in accordance with the Quran, don’t eat pork.

Police and the FBI are searching for suspects who were seen on security camera footage driving by in a red pickup truck late Sunday night before circling back and throwing an item–which could have been the pig’s head–at the mosque, Philly.com reports.

“It’s just a pig’s head—that’s not a big deal; but it does send a message,” mosque spokesman Marwan Kreidie told the Washington Post. “I think people are worried that if they do a pig’s head, they could do something more violent in the future.”

The incident is the latest in a string of anti-Muslim incidents in America in the wake of the Paris attacks, which were claimed by the Islamic State terrorist group. Kreidie told ABC 6 that the mosque also received a threatening phone call the day after the Paris attacks, with someone leaving a voicemail message that blamed the members of the mosque for the terrorist attack in France.

The Council for American-Islamic Relations (CAIR), a civil liberties and advocacy group, says that since the attacks nearly a month ago, Muslims in America have faced “an unprecedented backlash” in the form of discrimination and outright violent attacks in some cases. In a report released on Nov. 24 the group listed at least 27 incidents where Muslims were targeted after the Paris attacks.