William Celli, who has declared support for Donald Trump, was arrested in California on Sunday – despite warnings to authorities as early as 4 December

Police in California waited more than two weeks before arresting a man who posted an image of a homemade bomb on Facebook amid messages professing support for Donald Trump and opposition to Muslims, the Guardian can reveal.

William Celli, 55, was arrested on Sunday in Richmond, California, after police raided his house and discovered a suspected homemade bomb. He has been charged with two counts of suspicion of making criminal threats and possession of an explosive device.



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Police were first warned about Celli more than two weeks ago, when one of his Facebook friends raised the alarm about anti-Islamic postings he had uploaded along with an image purporting to show a homemade device.

The postings included the claim that members of his local mosque celebrated the Paris attacks and the suggestions that all Muslims in America should be sent back to their “country of origin”.



Maria DiLoreto Banks, a childhood friend of Celli who took a screen grab of the postings when they appeared on her feed, has shared the images with the Guardian. She provided the same information to the police more than two weeks ago. “I just thought they dropped it because I never heard anything,” she said.

The posts include derogatory references to Hispanics and Muslims as well as a photograph of an apparent pipe bomb resting on a table outside a house. Celli appears to have posted: “Built it all by myself lol” and “Home Depot don’t sell stuff is big here’s a crude device for you”.

Facebook Twitter Pinterest Celli called for Muslims to be returned to their ‘country of origin’. Photograph: Facebook

The image of the bomb was posted the same day – 4 December – that Celli is alleged to have stood outside his local mosque threatening to kill congregants. That incident was also reported to police.

Celli’s Facebook page also contained praise for the Republican presidential frontrunner. “Donald trumps on again I’m happy leaders okay but this guys a great point man I’ll follow this MAN to the end of the world,” Celli posted on October 21.



The investigation began on 4 December, when members ofRichmond mosque Masjid al Rahman, also known as the Islamic Society of West Contra Costa County, reported to police that a man, now believed to be Celli, had yelled threats as members left from a Friday afternoon service.



Facebook Twitter Pinterest William Celli posted several anti-Muslim comments on Facebook. Photograph: Facebook

Abdur Rahman, a member of the mosque for 19 years who was present at the time, told the Guardian that Celli was screaming: “I’m going to kill you all” from a Burger King parking lot across the street. Rahman said that Celli “didn’t look like a crazy person”, but “was a little agitated and taking video of the congregants”.

Celli continued “ranting and cussing” for about 10 minutes, Rahman said, before leaving and telling another congregant “I will come back”. Police arrived at the mosque about three hours after Celli departed, according to Rahman, and took a report.

Meanwhile, across the other side of the country, in Connecticut, Banks said she became “nervous” when she saw her old friend’s Facebook posts and took screenshots of them. Two days later, she handed them into her local police station in Wethersfield, Connecticut. “I know Billy, but I haven’t seen him in a while and I didn’t feel comfortable because God forbid something happened and I didn’t do anything about it,” she added.

Later that night, on 6 December, Banks said she received a phone call from a California police agency following up on her report.

“They got the post and they wanted to know if it was still there and if I wanted to remain anonymous and what I knew, and to verify that all the information from the Wethersfield police department was correct and I wasn’t some flake,” she said. That was the last she heard from law enforcement.

Celli was not arrested until Sunday, 16 days after police were warned that a man fitting his description had been threatening congregants at the mosque, and 14 days after Banks raised the alarm over his Facebook post of a bomb. He was taken into custody without incident, while the bomb squad removed and “rendered safe” a possible explosive device, according to Jay Hill, commander of the Walnut Creek bomb squad, which responded to the call to aid Richmond police.

Police evacuated neighbors before the bomb squad investigated the device. Hill said he was unable to confirm whether the device was a viable bomb, but added: “It did look like an explosive device.”

Richmond police declined to confirm or deny whether the screen grabs handed into law enforcement by Banks were in their possession. Neither did they respond to questions over the apparent two-week delay of Celli’s arrest.



Lieutenant Felix Tan, chief of staff of the Richmond police department, said officers “worked tirelessly for days to track this suspect down”.

“When they caught wind of this, they wasted no time and rushed into action and were able to find the suspect and the house and potentially stop a tragedy from happening,” he said.

However members of the Islamic Society of West Contra Costa County have apparently spent weeks trying to persuade police to take the case of the man seen making threats against them more seriously.

They became so concerned that, a week after the incident, they contacted Richmond councilman Eduardo Martinez for assistance. Martinez told the Guardian that he contacted the chief of police to inquire about the investigation and was told “they didn’t have enough evidence call it a hate crime”.

Facebook Twitter Pinterest Celli claimed members of his local mosque were celebrating on the day of the Paris attacks. Photograph: Facebook

Banks, who grew up next door to Celli’s family in Connecticut, said although she had not seen him in person in many years, she remembered him as “a normal guy” and a “gear head” who liked cars.

Celli’s grandfather was an immigrant who served in the Italian army in the first world war, and his father is deceased, according to an obituary. Celli’s Facebook page describes him as a self-employed plumber who recently celebrated “29 years of marriage”.

The incident involving Celli at the mosque, and his alleged posting of a pipe bomb on his Facebook page, both occurred days before Trump unveiled his incendiary policy of temporarily banning Muslim foreigners from entering the country.

However Celli’s alleged ranting online has coincided with a surge in anti-Muslim sentiment in the wake of terrorist attacks in Paris and San Bernardino – which civil rights groups argue has been stoked, in part, by conservative political figures such as Trump.



Last week Vanita Gupta, the head of the civil rights department at the Department of Justice, said there had been a surge in attacks against Muslims in recent weeks, which she connected to “divisive rhetoric”.

Celli is being held at the Martinez detention facility on $525,000 bond.