A California man charged with possessing an explosive device and threatening to kill Muslims will spend 90 days in jail and serve three years probation after accepting a plea deal.

KRON reports 55-year-old William Celli, an admirer of Republican front-runner Donald Trump, pleaded guilty last week to a charge that he attempted to violate the free exercise of civil rights. In exchange for his guilty plea, the Contra Costa County District Attorney’s Office has dropped a charge of making criminal threats as a hate crime.

Facebook William Celli.

Celli was arrested on Dec. 20, 2015, days after he yelled “I’m going to kill you all!” outside the Islamic Society of West Contra Costa County. After police got a tip that Celli was building homemade explosives with the intent of targeting local Muslims, they executed a search warrant at Celli's home.

There, they found a suspicious device and detonated it.

Celli, a self-employed plumber, made a series of xenophobic, Islamophobic and pro-Trump Facebook posts in the months leading up to his arrest.

In an Oct. 21, 2015 post, Celli wrote that Trump was a "great point man" who he would "follow to the end of the world."

In a post on Oct. 25, 2015, Celli seemed to express outrage over a supposed influx of Muslim immigrants, writing, "Kiss your Christian asses goodbye."

In another post, he lamented that he "lost 30% of my business to to Hispanics coming to my country under false pretenses ... and freeload in construction or in the blue collar sector they need to go back home lets not talk about the welfare they suck dry."

As part of his plea deal last week, The Richmond Standard reported, Celli is not allowed to have an active Facebook page.

At a time when attacks on mosques and Muslim individuals are at an all-time high, this will send a message that such actions will have consequences.” Zahra Billoo, executive director at the San Francisco-Bay Area chapter of the Council on American-Islamic Relations

Celli's arrest in December came amid a frightening surge in anti-Muslim hate crimes and rhetoric after terror attacks in Paris and San Bernardino. In the month leading up to his arrest, the number of hate crimes against Muslims in the United states tripled.

And on Dec. 8, just two weeks before Celli's arrest, Donald Trump called for a ban on all Muslims entering the United States.

“We welcome the jail time handed out in this case and are appreciative of the cooperation and support from law enforcement and the district attorney’s office shown to the local Muslim community,” Zahra Billoo, executive director at the San Francisco-Bay Area chapter of the Council on American-Islamic Relations, said in a statement Thursday. “At a time when attacks on mosques and Muslim individuals are at an all-time high, this will send a message that such actions will have consequences.”

CAIR added in a statement that after Celli's arrest, the Islamic Society of West Contra Costa County, like other mosques in the Bay area, has stepped up security and hired more private guards.