Fire destroyed a mosque at an Islamic cemetery and investigators believe it was could have been an arson or hate crime.

"We can't rule that out until we look at everything," said San Bernardino County Fire Department (search) spokeswoman Tracey Martinez. She said federal investigators had been called into the case.

The fire early Friday at the United Islamic Youth Organization (search) mosque is considered suspicious because the 1,500-square-foot building did not have electricity or gas service.

Only two walls remained standing after the fire, which also destroyed Korans and prayer rugs, said Seyed Mousavi, a mosque board member.

The mosque served as a spiritual center for visitors to a cemetery of 600 graves, which all face toward the holy city of Mecca (search).

"The only thing we're afraid of is that someone who doesn't like Muslims found out this is the only Islamic cemetery in the U.S.," Mousavi said.

"The significance of that cemetery is great to Muslims in Southern California, and if this is arson, that's a big insult to our community," said Mustafa Kuko, director of the Islamic Center of Riverside. "The Muslim looks at the mosque as a home. They don't have all the clues yet, but it's like someone has burned down one of our homes."