Pork and pork byproducts are haram, or forbidden, in Islam.
Ibrahim Hooper, national communications director for the Council on American-Islamic Relations, told CNN that his group has seen a spike in violence and anti-Muslim sentiment since last month's terror attacks in Paris.
"The anti-Muslim atmosphere we've been seeing in recent weeks is, in many ways, worse than it was after the 9/11 attacks," he said. "After 9/11, the anti-Muslim rhetoric was on the fringes. ... Now it's at the mainstream."
In his experience, mosque spokesman Marwan Kreidie told CNN that the incident involving the pig's head is unusual. He described the neighborhood where the Al-Aqsa Islamic Society is located as tolerant and diverse.
When asked about Trump, he said that "words have consequences," but stressed that the problem is not contained to one person.
"Unfortunately, there appears to be an audience for this," said Kreidie.