In this courtroom sketch, Cesar Sayoc, left, appears in federal...

In this courtroom sketch, Cesar Sayoc, left, appears in federal court on Monday in Miami.  Credit: AP/Daniel Pontet

The Florida man accused of sending pipe bombs to 15 prominent Democratic officials, donors and celebrities began plotting his "domestic terror attack" as early as July, searching online for the addresses and photos of his intended targets, federal prosecutors said in a letter filed Tuesday.

The letter, sent by the U.S. Attorney's Office for the Southern District of New York, asked U.S. Magistrate Judge Edwin Torres to remand Cesar Sayoc, 56, without bail at a detention hearing Friday in Miami and to transfer the Brooklyn-born suspect to New York to stand trial.

"The evidence of the defendant’s terror campaign is still being collected but is already overwhelming," prosecutors wrote in the letter. "Because of the powerful proof that the defendant perpetrated these acts, he poses a substantial danger to the community. In light of the consequences at issue and the likelihood of conviction, the defendant is also a substantial flight risk."

The letter provides fresh details about Sayoc's plot, which the FBI said he hatched while living in a white van plastered with stickers praising President Donald Trump and depicting some of his intended targets, including former President Barack Obama and former Secretary of State Hillary Clinton, with red crosshairs.

The FBI said Sayoc's cellphone also had a photo of former first lady Michelle Obama's driver's license while several of the improvised explosive devices contained shards of glass "that could only have been intended to maximize harm to the defendant's victims," the letter said.

None of the bombs went off and there were no injuries.

FBI investigators said Sayoc used a laptop and cellphone to search for the addresses of Obama, Clinton, former Vice President Joe Biden, Democratic donors George Soros and Tom Steyer, Sen. Kamala Harris (D-Calif.), Sen. Cory Booker (D-N.J.), former Attorney General Eric Holder, former intelligence director James Clapper, former CIA Director John Brennan and CNN. 

The FBI recovered explosive devices sent to all of them, in addition to California Democratic Rep. Maxine Waters and actor Robert De Niro. All were frequent critics of Trump.

The laptop also had a file with the address of Rep. Debbie Wasserman Schultz (D-Fla.). Sayoc used Schultz's office as the return address for his pipe bomb packages, officials said.

Thus far, the FBI said it has evidence linking Sayoc to 10 of the makeshift bombs and latent fingerprints connecting him to two of the mailing envelopes.

Sayoc has been charged with interstate transportation and illegal mailing of explosives, threats to former presidents and certain other persons; threatening interstate communications and assault on former and current federal officers. He is likely to face additional charges, Manhattan prosecutors said. Sayoc could face up to 48 years in prison.

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