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On Thursday, prominent liberal critics of President Trump continued to report that they’ve received explosive devices in the mail, including actor Robert De Niro and former Vice President Joe Biden — an escalation of an unfolding saga that’s become the center of a major federal investigation and a political firestorm.

Official sources confirm that at least 10 suspicious packages — all containing suspected explosive devices — have been sent to the following people:

Hillary and Bill Clinton

Barack and Michelle Obama

Liberal donor George Soros

Former CIA Director John Brennan (via CNN)

Democratic Rep. Maxine Waters

Former Attorney General Eric Holder (which was sent to the return address of Rep. Debbie Wasserman Schultz’s Florida office)

Robert De Niro

Joe Biden

A manhunt is underway for the person (or people) responsible for the packages. The FBI said the packages addressed to the Obamas, Clintons, Soros, Brennan, and Holder were all sent in yellow manila envelopes and listed the same return address of Democrat Rep. Debbie Wasserman Schultz in Florida. Federal law enforcement officials later said that the additional five packages sent to Waters, DeNiro, and Biden were “similar in appearance” to the others.

Trump injected himself into the storyline on Wednesday, first giving relatively staid remarks from the White House and then going on to appear at a political rally in Wisconsin, where he blamed the media for public rancor while omitting his own history of vilifying his political opponents and endorsing political violence.

No one has been injured by the bombs, but they’ve spurred a wave of concern about the possibility of political violence. Here’s what we know so far.

Bomb recipients

Authorities are not speculating on a possible motive, but we do know that each target is a liberal critical of Trump, someone whom Trump has attacked in recent months or years, or both. The Clintons, Obamas, and Biden are among the nation’s most prominent Democrats. Soros is a progressive donor and the target of right-wing conspiracy theories. Trump has repeatedly attacked Waters on Twitter and at rallies. De Niro gave a speech at the Tony Awards in which he said, “Fuck Trump.”

The devices

NBC News obtained an image of one of the devices. FBI official Bryan Paarmann said at a press conference on Wednesday in New York that they appeared to be pipe bombs.

NBC News Exclusive: Below is a photo of one of the suspicious devices intercepted by law enforcement and obtained by NBC News: pic.twitter.com/sB9D8dhhaW — Tom Winter (@Tom_Winter) October 24, 2018

The bomb sent to CNN was decorated with a sticker that was a parody of the ISIS flag with the phrase “Get Er Done,” according to NBC News. The return address was “DEBBIE WASSERMAN SHULTZ” (misspelled), with the Congress member’s Florida office listed.

The bomb sent to CNN’s offices also included an envelope of white powder, according to the NYPD.

What we know about the attempted bomber

So far, the perpetrator’s identity and motives are unknown — as is whether the bombs are being sent by one person, or multiple people working together. FBI Director Christopher Wray has asked for the public’s help in finding the perpetrator or perpetrators, but law enforcement agencies have revealed nothing about any clues they might have.

Trump’s response

After a straightforward statement Wednesday afternoon calling for unity and referring to the bombings as “despicable,” President Trump quickly turned to a usual foe: the media.

At his rally on Wednesday night, he warned against political violence, but got in a few barbed allusions to Democrats (and winked at the audience about his unusually somber tone, repeatedly saying that he was on his best behavior). He warned against “mobs” as a form of political violence, in line with his rallying cry heading into the midterms: “Jobs Not Mobs.”

On Thursday, he was more pointed, tweeting that “a very big part of the Anger we see today in our society is caused by the purposely false and inaccurate reporting of the Mainstream Media.”

All of this — and Trump’s previous responses to violence committed by his supporters — has called into question whether he can play the uniting role that an incident like this would usually require. That’s a role Trump has often delegated to Vice President Mike Pence.

The timeline

The New York Times reports that devices were found on Monday at the home of liberal donor and billionaire George Soros in a New York City suburb.

Late Tuesday night, a suspicious package, later confirmed to contain an explosive device, was discovered near the property of Bill and Hillary Clinton’s home in upstate New York. It was discovered by an employee who checks the Clintons’ incoming mail, according to the Secret Service.

Early Wednesday morning, a suspicious package was sent to former President Barack Obama and Michelle Obama in Washington, DC, but was intercepted by Secret Service during routine screenings, according to the agency.

White House press secretary Sarah Sanders said the White House condemns the “attempted violent attacks” and called them “terrorizing acts” that are “despicable.”

NEW: statement from ⁦@PressSec⁩ on suspicious packages sent to Obama and Clinton pic.twitter.com/3OB4StwmUH — Abby D. Phillip (@abbydphillip) October 24, 2018

Trump’s first response was a retweet of the Vice President. Trump said “wholeheartedly” agreed with Mike Pence’s condemnation of the incidents.

Trump, later speaking at an event on opioids at the White House on Wednesday, said that the safety of the American people is his “highest and absolute priority.” He said it was a time to “unify,” adding that “acts of political violence of any kind have no place in the United States of America.” Trump, who was briefed on the incidents ahead of his remarks, said a “major federal investigation” is being conducted.

CNN’s New York office was also evacuated on Wednesday, with anchor Jim Sciutto tweeting that the police bomb squad was there and they’d been told of an explosive device being received. The NYPD responded and dispatched investigators to Columbus Circle in Manhattan, where CNN’s office at the Time Warner Center is located.

Breaking: CNN NY office evacuated. Police bomb squad is here. We’re told of explosive device received. @CNNnewsroom — Jim Sciutto (@jimsciutto) October 24, 2018

The FBI confirmed that the package sent to CNN was addressed to former CIA Director John Brennan — who is a contributor for NBC and MSNBC, but not CNN.

This photo obtained by @ABC and confirmed by two law enforcement sources shows the device recovered from @CNN by the NYPD bomb squad. pic.twitter.com/HFzTMSoJXG — Gio Benitez (@GioBenitez) October 24, 2018

NYPD Commissioner James O’Neill said at a press conference that the package sent to CNN contained what appeared to be “a live explosive device.” Investigators also discovered white powder inside the package found at CNN, but FBI assistant director William Sweeney said at a press conference Thursday that the powder “did not present a biological threat.”

MORE: "Additionally, there was an envelope containing white powder that was discovered as part of that original packaging," NYPD Commissioner James O'Neill says of suspicious package sent to Time Warner Center https://t.co/KgAu4w874O pic.twitter.com/5KNDF2LB5o — CBS Evening News (@CBSEveningNews) October 24, 2018

New York Democratic Gov. Andrew Cuomo at the same conference said a package had been sent to his office in Manhattan. The NYPD later said that the package was unrelated, and there was no device.

The earlier suspicious package at Governor Cuomo’s office in midtown has been cleared by NYPD personnel. It was unrelated. And there was no device of any kind — J. Peter Donald (@JPeterDonald) October 24, 2018

The FBI said a suspicious package went to Florida Democratic Rep. Debbie Wasserman Schultz’s office, but it was not intended for her. The New York Times and CNN reported the package was sent to Eric Holder, the US attorney general under Obama, but it was misaddressed and it ended up at Wasserman Schultz’s office, which was listed as the return address.

WASHINGTON (AP) — FBI confirms 'suspicious package' went to Rep. Wasserman Schultz' office in Sunrise, FL. — Kyle Griffin (@kylegriffin1) October 24, 2018

Wasserman Schultz’s office in Florida was listed as the return address multiple, according to the FBI — though her name was incorrectly spelled as “SHULTZ” on the parcels.

The FBI said five packages were sent in yellow manila envelopes lined with bubble wrap and affixed with a printed label and six “Forever” stamps.

Statement on the FBI’s Investigation of Suspicious Packages https://t.co/wwXDpyNt3A pic.twitter.com/rXu1wBAQHj — FBI (@FBI) October 24, 2018

The FBI later confirmed that two suspicious packages had been sent to Rep. Maxine Waters (D-CA), both containing devices similar to those sent to Obama, Clinton, and others. One had been intercepted at a congressional mail processing facility and then turned over to the FBI, according to the New York Times. Another was discovered at a mail processing facility in South Los Angeles on Wednesday, reported the LA Times.

Thursday morning, another suspicious package containing an explosive device was found at the production company of Robert De Niro, according to the New York Times — an actor who has openly criticized Trump.

Law enforcement officials said former Vice President Joe Biden had also been a target. At least two packages addressed to him were discovered by investigators in a Delaware mail facility, report CBS and the Washington Post.

The FBI confirmed Thursday that Biden and DeNiro had been sent parcels. The packages were “similar in appearance” to the others, the bureau said.

The FBI will analyze the packages at its labs in Quantico, Virginia. FBI Director Wray said in a statement that this investigation is the “highest priority” for the bureau. “We have committed the full strength of the FBI’s resources and, together with our partners on our Joint Terrorism Task Forces, we will continue to work to identify and arrest whoever is responsible for sending these packages,” he said.

What we don’t know