"Every day you turn on the TV, you see Muslims trying to kill Americans," said Linn, a truck driver from St. Joe who had been arrested outside his Fort Wayne workplace.
When asked by a federal judge whether he thought all Muslims are terrorists, he answered: "I'd say most of them are."
A deal between prosecutors and Linn, 52, calls for him to be sentenced to 20 years next April. He pleaded guilty to intentionally damaging and destroying religious property and two gun-related charges.
U.S. District Judge Jack Zouhary told Linn that his acts were an attack on all places of religion and that the mosque was a symbol of peace.
"You are no better than the terrorists or extremists you sought to punish," Zouhary said.
Prosecutors said Linn drove about two hours from his home to suburban Toledo on Sept. 30 and broke into the mosque where he poured gasoline on the rug and lit it on fire.
He estimated that he had drunk 45 beers over several hours before he decided to drive to Ohio.
Linn had several firearms in his car and carried a gun into the mosque, which was empty at the time.
U.S. Attorney Steven Dettelbach said it was fortunate no one was there. "This is a man who had intolerance in his heart and acted with hate," he said. "We can count ourselves lucky."
Linn said he went room by room to make sure no one was in the building. "I was drinking a beer while I was doing that," he said.
A sprinkler system extinguished the blaze, leaving smoke and water damage in the prayer room of the facility, whose golden dome is a landmark along Interstate 75. No one was hurt.
Members of the Islamic center have been unable to use the building and expect repairs to be finished by the end of March.
Dr. Mahjabeen Islam, president of the Islamic Center, said its members been overwhelmed by support from the community and churches. But she was saddened by Linn's statements in court.
"It was heart-wrenching to hear him speak because the ignorance and intolerance is still palpable," she said. "This is an individual who knows nothing about Islam."
A woman who knows Linn had identified him in publicized surveillance images and contacted authorities, according to a court affidavit.
The woman told law enforcement officers that Linn had made comments complaining about the deaths of U.S. military members in the Middle East, recent attacks on U.S. embassies and Muslims' angry reactions to an anti-Islam video posted online.
Assistant U.S. Attorney Ava Dustin said Linn told his son two weeks before the fire that he wanted to burn down the mosque.
Linn said he started to have second thoughts when he drove home. "Coming back, I thought, 'What in the heck did I do?'"
"I feel bad I did it," he said. "It's a little too late now."