HILLSBOROUGH, N.C. >> Investigators combed through shards of glass, looked for residue of flammable accelerant and tried to narrow down the overnight hours when someone torched a local Republican Party office by throwing a flammable device through the window.

Local party officials reopened a makeshift operation on folding tables outside the office today while uniformed police looked on. Plainclothes investigators looked for evidence at the scene as state, local and federal investigators divided up leads.

Meanwhile, the head of the Arizona Republican Party said today that its office received a bomb threat and it likely will hire private security guards.

Arizona Chairman Robert Graham says the office got a call around 3:15 p.m. from an adult who said there was a bomb in the building.

Phoenix police responded and gave an all-clear to the situation about two hours later.

The Hillsborough, N.C. mayor said he wasn’t aware of any surveillance footage from the immediate vicinity, and the office sits where there wouldn’t normally be foot traffic late at night — in a decades-old retail complex that backs up to a wooded area and is set back from a main road.

A bottle filled with flammable liquid was thrown through the window of the Orange County Republican Party headquarters early Sunday, damaging the interior before burning out, according to authorities. Someone also spray-painted “Nazi Republicans leave town or else” on a nearby wall. The office was empty and no one was injured.

“We have had people working on it from three different federal agencies, state agencies, our local folks, all day today, running down leads, working different parts of the investigation,” Hillsborough Police Chief Duane Hampton told The Associated Press in a phone interview.

He declined to say how confident he was that the evidence would lead to an arrest.

North Carolina’s Republican Gov. Pat McCrory spoke to reporters at the office, saying he’d never seen anything like it in his political career. McCrory, who’s been touring parts of the state ravaged by floods, said: “To come back near our state Capitol and see a broken window from a Molotov cocktail is unimaginable.”

He also questioned why it took Hillsborough authorities several hours after the 911 call to release information publicly Sunday, suggesting they had initially treated the crime as merely vandalism instead of something more serious.

But Hampton said federal agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives were called immediately and arrived on the scene within an hour of his own officers.

“I certainly don’t want anyone to think that we didn’t take this seriously because we realized the implications right away,” he said.

The graffiti and remnants of the fire were discovered Sunday morning by 68-year-old Bobbie Sparrow, whose Balloons Above Orange shop is next to the GOP headquarters. She came to feed stray cats before church when she noticed the graffiti shortly before 9 a.m.

“I saw the hate in it. And the only reason they used the side of my building, because it was a blank canvas for a message to the Republican Party people,” she said in an interview. “I picked up my cellphone and called 911 and told them someone needed to get here immediately.”

County GOP chairman Daniel Ashley arrived Sunday morning to find the area roped off by yellow police tape. He said he believes whoever’s responsible intended to burn down the building.

“I definitely think the reason they spray-painted that building there was because they thought this one wouldn’t be here,” he said, standing in front of his office.

The violent act in the key battleground state has been condemned by public figures across the political spectrum, including Democratic presidential nominee Hillary Clinton and Republican nominee Donald Trump. McCrory’s challenger, the state’s Democratic Attorney General Roy Cooper also said the violence “has no place in our democracy.”

Democrats started a campaign to raise $10,000 to reopen the GOP office, meeting the goal in less than 40 minutes and “showing that Americans are thirsty for civility and decency,” wrote the GoFundMe drive’s creator, David Weinberger, a researcher at Harvard University.

“It’s a great gesture. We appreciate it a lot, but I don’t know how much of that we’re going to get to use because of the campaign laws,” Ashley said Monday.

The walls of the multi-room office were covered in black char, and a couch against one wall had been burned down to its springs. Shattered glass covered the floor, and melted campaign yard signs showed warped lettering at the office in the town about 40 miles northwest of Raleigh.

Registered Democrats outnumber Republicans 3-1 in Orange County, which also includes Chapel Hill and the University of North Carolina campus.

Blake Halsey, a 21-year-old college student who volunteers at the Orange County GOP office, answered calls Monday at a folding table outside the shattered front window. He grew up in the area and described the town as a “melting pot” for all political views.

He said the attack made him think about his personal safety because he’s worked after-hours recently at the office.

“It’s sad to see America go this way,” he said. “The Constitution says we have free speech. But free speech does not mean you can throw a fire bomb in there.”

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