A spokesman for ATF said today that although they aren't ready to say the fire was intentional, an accelerant was found.
"We're leaning toward arson," Special Agent Glenn Anderson said on MSNBC.
The plans for a mosque have sparked protests and acts of vandalism and put the mosque in the political spotlight. The state's lieutenant governor and gubernatorial candidate, for example, suggested at a Q&A that Islam isn't a religion, but a cult.
A spokeswoman for the Islamic Center of Murfreesboro called the fire "an atrocious act of terrorism."
"We believe that this event was instigated by the hate campaign that our Muslim community has been subjected to recently," Camie Ayash said in a statement.
The sheriff's office is also investigating reports of shots fired near the site on Sunday afternoon. Members of the community center were gathered at the site doing an interview with local media when, one member said, they heard nine gunshots. He said he wasn't sure if the shots were fired at them, but reported it nonetheless.
"To say we're nervous is a huge understatement. It's terrorism," he said.
But the federal agencies won't go that far.
"I haven't seen any indications that this is any type of domestic terrorism," Anderson said, and there are "no indicators that we're aware of that would put us in the position of a hate crime. I wouldn't deny that there's a lot of tension in the community, on both sides, but I don't think there's anything that points to a hate crime at this point."
A spokesman for the FBI confirmed to TPMmuckraker that they were called in as the lead federal agency in the case of civil rights abuses or domestic terrorism, but said the fire is still under investigation. He noted that two past incidents at the mosque site -- someone wrote "not welcome" on a sign and later, the sign was destroyed -- were classified as vandalism.
Kevin Fisher, a resident who has been a lead organizer of mosque opposition, released a statement condemning the fire.
"I condemn any violence against anybody," Fisher told TPMmuckraker in a phone interview. He urged anyone who has information about the fire to step forward. He also cautioned against jumping to the conclusion that a mosque opponent set the fire and said everyone "should simply take a step back."
"I think it's terrible that people are jumping to conclusions," he said, "and calling it an act of terror. It's sad. ... I think it's kind of irresponsible to immediately start labeling it as such."
The sheriff's office and the Islamic center have not returned calls for comment.