A series of crudely made explosive devices mailed to top political leaders began surfacing across the country on Wednesday, with the list of names growing hour by hour as authorities scrambled to intercept them and learn who was behind them.

By Wednesday afternoon, the FBI confirmed that the intercepted suspicious packages, all similar in appearance and containing “potentially destructive devices,” were mailed this week to former Secretary of State Hillary Clinton; former President Barack Obama; former Attorney General Eric Holder; and former CIA Director John Brennan, care of CNN.

All five of the packages were mailed in manila envelopes with bubble wrap interior, the FBI said, along with computer-printed address labels and six Forever stamps. Each of the bombs had a return address for Democratic Rep. Debbie Wasserman Schultz’s office in Florida.

In at least one case, a bomb was accompanied by a white powder that was being tested, NYPD sources told The Daily Beast. None of the devices exploded, and no one was injured. All of the packages will be analyzed at the FBI’s research facility in Quantico, Virginia.

Authorities are working to determine a motive for the attempted attacks, but the common thread among the packages was that they were all addressed to top players in Democratic Party politics.

The scare began Monday night when the first bomb surfaced outside the suburban Westchester County home of George Soros. The second, which was addressed to the home shared by Bill and Hillary Clinton, was intercepted by U.S. Secret Service agents on Tuesday night. A third, addressed to Obama, was uncovered by Secret Service agents in Washington, D.C., on Wednesday morning.

Soon after, reports emerged one after another from across the country—some true, others that had to be be taken back or clarified—fueling a panic that has gripped the nation.

As federal agents investigated those packages, authorities in New York dispatched bomb squads to the Time Warner Center in midtown Manhattan, home to CNN, where the building was fully evacuated.

Senior law-enforcement officials initially confirmed to The Daily Beast that a suspicious device—described as a “pipe with wires”—was found in the CNN mailroom. They relayed that the NYPD bomb squad described the device as “crude but functional,” meaning it had potential to do harm.

“The packages were immediately identified during routine mail screening procedures as potential explosive devices and were appropriately handled as such,” the Secret Service said in a statement on Wednesday, regarding the parcels sent to the former presidents’ homes. “The protectees did not receive the packages nor were they at risk of receiving them.”

The Newcastle Police Department, which covers the hamlet of Chappaqua, where the Clintons reside, confirmed to The Daily Beast that they assisted the FBI and Secret Service in investigating the suspicious package sent to the Clintons.

At around 10:10 a.m. on Wednesday, CNN anchors Poppy Harlow and Jim Sciutto interrupted a segment on the two bombs sent to the Democratic heavyweights because of an alarm in the newsroom.

“We’re going to jump in there is a fire alarm here we are. We are going to find out what the latest is here at CNN and we are going to be right back,” Harlow and Sciutto said.

After the commercial break, Sciutto and Harlow had evacuated, but continued to report on the incident from their cellphones on the street outside the office building while a fellow colleague anchored from Washington. They were accompanied on-air by several other CNN correspondents, who reported the situation in real-time from outside their headquarters.

CNN anchor Wolf Blitzer later reported that the device sent to the news outlet’s headquarters was specifically addressed to John Brennan, who served as Obama’s CIA director. Brennan does not work for CNN; he is an MSNBC contributor.

“We’ve seen this before, we’ve seen worse and we will not be intimidated,” Police Commissioner James O'Neill said during a press conference outside the CNN offices.

New York Mayor Bill de Blasio called the bomb threats an “act of terror.”

And a spokesman for the Sunrise Police Department in Florida confirmed to The Daily Beast that a building where Rep. Wasserman Schultz has an office was evacuated due to a suspicious package that arrived by mail.

CNN reported that the device was mailed to former Attorney General Eric Holder but because it was the wrong address, the package was returned to the congresswoman’s office, which was labeled as the return address.

News of the confirmed devices set off a cascade of other scares throughout Wednesday.

“I have been informed by U.S. Capitol Police that my Washington, D.C. office was the target of a suspicious package that has been referred to the FBI,” Democratic Rep. Maxine Waters said in a statement. “I am appreciative of the law enforcement entities who intercepted the package and are investigating this matter. I unequivocally condemn any and all acts of violence and terror.”

And a building housing both the San Diego Union-Tribune and an office for Sen. Kamala Harris (D-CA) was evacuated because of a stack of packages left outside the building. And the office of the NBC and CBS affiliates in Fresno, Calif., were locked down because of an unattended box—but there was no indication they contained explosives or were connected to the other packages.

Adding to the chaos, conflicting reports surfaced that authorities intercepted a package addressed to the White House at Joint Base Bolling in Washington, D.C. The Secret Service, however, issued a statement saying those reports were untrue.

Gov. Andrew Cuomo claimed during a presser that authorities were investigating a package sent to his Manhattan office. However, NBC later reported that senior officials said it was a “hoax letter” with no connection to the other packages.

Wednesday’s bomb scares come just two days after a suspicious device was found in the mailbox of billionaire philanthropist Soros’ home in the same county as the Clintons’ residence. As the FBI confirmed on Wednesday, that package was similar to the ones sent to Obama, Clinton, Brennan, and Holder.

At the New York headquarters of Soros’ premiere political-philanthropic initiative, the Open Society Foundations, staff had been receiving an uptick in threatening phone calls and hostile social-media posts over the past several weeks. Nothing, however, has escalated on Wednesday.

“We’d interpreted this as a sign of escalated vitriol and the rhetoric of hate,” said Open Society’s communications director Laura Silber. “We’re appealing to the leaders of this country to tone down the violent political rhetoric.”

Silber said Open Society’s mood on Wednesday was “calm” and staff are still at work. But the foundation is taking additional security precautions, aided by the NYPD, which Silber said had been “very supportive, from the moment of the first reports” of a package received at Soros’ home.

“We condemn the attempted violent attacks recently made against President Obama, President Clinton, Secretary Clinton, and other public figures. These terrorizing acts are despicable, and anyone responsible will be held accountable to the fullest extent of the law,” White House Press Secretary Sarah Huckabee Sanders said in a statement on Wednesday.

Vice President Mike Pence issued a similarly worded statement, to which President Trump quoted and added: “I agree wholeheartedly!”

“The United States Secret Service and other law enforcement agencies are investigating and will take all appropriate actions to protect anyone threatened by these cowards."

Donald Trump has been briefed on the packages and is taking the situation “extremely seriously,” a senior White House official told NBC News.

John Cohen, a former acting undersecretary for intelligence at the Department of Homeland Security, described to The Daily Beast what investigators will look for going forward.

“Law enforcement will be able to get DNA from the packaging and other parts of the device,” he explained. “They will be able to glean a lot of information from the materials used to construct the device. An explosive device doesn’t have to be complicated to be deadly. If this is an inexperienced bomb maker, there will be forensic evidence on the device.”

—Erin Banco contributed reporting.