A threatening, hand-written letter arrived Wednesday at Islamic centers in Ann Arbor and East Lansing.

The letter called Muslims "a vile and filthy people."

It referred to Donald Trump as "the new sheriff in town," and warned, "You Muslims would be wise to pack your bags and get out of Dodge."

The letter said Trump is "going to do to you Muslims what Hitler did to the Jews."

According to Dawud Walid, executive director of the Michigan Chapter of the Council on American Islamic Relations, the letter was also sent to other mosques around the country.

Walid said the letters were postmarked from California, and the mailings are under investigation by the U.S. Postal Service.

"I want to see president-elect Trump speak out very robustly against all of this hate that's being done in his name," said Walid.

Walid said there's been a spike in anti-Muslim incidents in Michigan since Election Day. They include school bullying, road rage directed at Muslims, and harassment.

"There is fear, but our message to our community members, to our congregation, is to really publicize the overwhelming support that we've received," said Eid Farha, president of the Board of the Islamic Center of Ann Arbor.

Farha said they're using the incident as motivation to build bridges with non-Muslims, city government, local police and interfaith groups.

"It is very sad that there are people out there who want to promote hatred and bigotry toward minorities, especially targeting the Muslim community. But at the same time here in East Lansing, we have received overwhelming letters and messages of support and love," said Sohail Chaudhry, the imam at the Islamic Society of Greater Lansing. "So we believe that there are more people out there who still believe they need to love their neighbors and be a welcoming community towards all and stand up for rights for all people."

"Since Election Day, we have received emails, phone messages, even people have dropped by the center from different churches, the neighbors around the Islamic Center, with flowers, with cards," Chaudhry said.