Daniel George Fisher, 57, appeared in federal court in St. Paul Wednesday after being charged with obstruction of persons in the free exercise of religious beliefs.

Fisher, now homeless, lived less than three blocks from a new Tawfiq Islamic Center at 2400 Minnehaha Avenue last year when he mailed an anonymous letter threatening "to blow up your building with all you immigrants in it," according to a sworn affidavit from FBI special agent Kevin Kane.

The letter, received by the mosque on Sept. 30, 2015, also included profanities, racial and ethnic slurs and "other derogatory comments about the religious and cultural practices of the members" of the mosque, Kane said. FBI fingerprint specialists discovered two sets of prints on the letter, one belonging to a Tawfiq member who opened the envelope and another set belonging to Fisher.

Fisher has not yet been assigned a defense attorney in the case.

In a June interview with agents, Fisher confessed to writing the letter in hopes that it would scare the Islamic center members away from building the new mosque. Kane said Fisher also told agents "he had become increasingly angry with Muslims since 9/11." Fisher used a false return address and did not sign the letter because he wanted the mosque to believe it could have been authored by "anyone in the area," Fisher told agents.

The center is a nonprofit organization established to serve the Oromo Muslim community in Minnesota.

In a statement Wednesday, U.S. Attorney Andrew Luger said those who seek to infringe on others' rights to practice their faith are violating the law but also are "ignoring a freedom that our founders held so dear."

Jaylani Hussein, executive director of the Minnesota chapter of the Council on American-Islamic Relations (CAIR), said he routinely tells area Islamic centers to take threats seriously, "especially now, when mosques are under threat of attack across the state."

Hussein said CAIR has received three similar reports in 2016 and has since begun offering booklets that detail safety precautions mosques should take. Hussein said he encourages any mosque that receives a threat to contact local law enforcement officials and the FBI, which can bring additional resources to hate crime investigations.

"We welcome the effort in taking this issue seriously to ensure the safety and security of Muslims in Minnesota," Hussein said.

Earlier this month, CAIR called on state and federal law enforcement authorities to investigate an incident of vandalism at a Mankato Islamic Center.

Also on Wednesday, the U.S. Department of Justice announced a 15-year prison sentence for a 26-year-old man who set fire to a Somali restaurant in Grand Forks, N.D., last year.

"Threats and intimidation against people because of their religious beliefs will never be tolerated by the FBI," said Richard T. Thornton, special agent in charge of the FBI Minneapolis Division, in a statement announcing the charge against Fisher on Wednesday.

Stephen Montemayor • 612-673-1755

Twitter: @smontemayor