NBC 7 has learned that law enforcement officials, including the FBI, have been notified of a threatening letter with an unknown substance inside sent to a San Diego mosque, an act one group is calling a hate crime.
The Islamic Center of San Diego in Clairemont Mesa received a signed letter in the mail that allegedly includes a threat specific to their location and other mosques located in San Francisco, Los Angeles and Oakland.
The envelope included a mysterious substance, though the FBI later confirmed it was harmless. A member of the mosque told NBC 7 the name signed to the letter was not known by the center’s leadership.
Details of the letter were not revealed, though a representative from the Council for American-Islamic Relations says it contains the words "death sentence." The spokesperson called the letter a hate crime and is asking the Muslim-American community to be on the lookout, reporting any threats to local authorities.
"It's a shock because this is the country where everybody has the freedom of religion, of speech, of opinion, of creed or whatever and we are no different than any other people," said Walid Bishawi.
On Friday, there was a heightened sense of security at the mosque, with police cruisers in the parking lot with the center's own security guard. However, most people who attended afternoon prayers say they don't feel afraid.
Leaders at the center handed out fliers and pamphlets about safety protocols, and they plan to hold a public safety expo during an event Saturday.
San Diego Police referred NBC 7's request for information to the FBI.
Agents confirmed they are reviewing facts and circumstances surrounding the incident and letter, and the case is still under review.
Between 2011 and 2012, 51 mosques nationwide have been targeted or attacked, the council says.
Anyone with information can contact the FBI at (858) 320-1800.