Transcript for How investigation into suspected mail bomb campaign is unfolding
Reporter: Tonight, a nationwide investigation and manhunt under way. I can say with certainty that we will identify and arrest a person or people responsible for these acts. Make no mistake. Reporter: In search of the bomb maker and those who may have mailed them, ten separate packages containing suspected explosive devices all addressed to prominent critics of president trump. From New York to Los Angeles, Florida to Washington, D.C., and Delaware. It's absolutely terrorism because it's an effort to use violence to make a political impact. That's the definition of terrorism. Reporter: Law enforcement now chasing leads in southern Florida where officials suspect some of the potential bombs may have originated. They're not going to move too fast because they want to make sure they cover all their bases so this could take a longer time than Normal. That's something that will not be good for the public, especially in light of the fact that there is an election coming up in 12 days, and everybody wants to know who did this. Reporter: Early this morning in New York City, a suspicious package intercepted, this one addressed to actor Robert de Niro. At approximately 6:30 A.M., the NYPD bomb squad removed a device from the offices of Robert de Niro in the tribeca neighborhood. Reporter: Before sunrise, a bomb containment vehicle whisked away a suspected pipe bomb to a secure facility. The man hired to go through de Niro's mail is an retired NYPD detective and had seen the other packages on the news. The package targeting de Niro shared the same characteristics as the others. Six American postage stamps on padded yellow envelope. Remember, at this year's Tony awards, de Niro took aim at the president. It's no longer down with trump, it's Trump. Reporter: At the time, the president responding, calling de Niro a very low iq individual. Too many shots to the head by real boxers, he said. And federal investigators now believe all ten packages went through the U.S. Postal system, leaving postal employees now hypervigilant. We have over 600,000 postal employees out there right now so we have their eyes and ears looking for these packages. I will say in the postal network, we have found nothing in the last eight hours. Reporter: Postal inspectors interviewing make carriers and workers, checking mail tracking data, reviewing surveillance footage, all in an effort to determine where the packages were mailed from. But ABC news exclusively learning of a challenge. A number of these packages had no originated postmarks. Forensic experts now painstakingly dissecting the suspected bombs, each package a treasure-trove of evidence. The digital clocks inside, the pipe used to contain the device, the tape to hold it together, the wires, the suspected explosive powder, and glass used for shrapnel. They're collecting all the various components in these devices and they're cataloging them and they're figuring out where in the United States they would be sold. The agents are all over the country, going to these locations and seeing who bought these products, when, and where they bought them. From what I can see, this device is fairly basic, easily copied from a -- many of the manuals in the libraries and/or online. People can say they're crude, but if they function properly and kill, maim, or injure someone, then they are certainly a viable infernal machine. Reporter: Sources tell ABC news that agents are searching for any trace left on the envelope, even both side of the tape used on the suspected devices and from how the wires are twisted, they can tell if the bomber is left or right-handed. Hopefully somewhere along the way, the individual that did this or individuals left some type of DNA and/or fingerprint, even a fiber of hair would be helpful in identifying a suspect or suspects. Reporter: The first of ten bombs discovered Monday afternoon at the home of philanthropist George Soros in a suburb north of New York City. George Soros is one of the top funders of democratic causes over the last couple of decades. Reporter: Then late Tuesday night, another device, this one sent to Hillary Clinton, intercepted by the secret service before it reached her home in westchester county, new York. Just hours later, a third suspicious package intercepted in Washington, D.C., addressed to the home of former president Obama. The package was found at a screening facility located in Washington, D.C. The package was immediately identified during the screening procedure. Reporter: Then, yesterday morning, in New York City, CNN was reporting on the spate of suspicious devices when their own alarms began to ring. To have projectals, I mean, that's a -- excuse me, that sounds like a fire alarm here. We'll keep you posted on that. Reporter: That device was addressed to former CIA director John Brennan at the CNN address. Then, in Maryland, a package addressed to democratic California congresswoman Maxine waters, intercepted by capitol hill police. Then later, another device, also addressed to the congresswoman, was found at a postal facility in Los Angeles. In Florida, police rushing to the office of democratic congresswoman Debbie Wasserman Schultz. The device there had been addressed to former Obama attorney general Eric Holder, but it had Wasserman Schultz as the return address. Authorities do not believe Wasserman Schultz was the actual sender or associated in any way, according to our sources. Wasserman Schultz issuing a statement saying, this appalling attack on our democracy must be vigorously prosecuted and I am deeply disturbed by the way my name was used. Then, last night, two packages addressed to former vice president Joe Biden, both were intercepted at postal facilities in Delaware. And this morning, the tenth and latest package addressed to de Niro. Meanwhile, across the country tonight, a renewed debate over political rhetoric going too far. Last night in Wisconsin, the president condemned what he called political violence. We want all sides to come together in peace and harmony. We can do it. We can do it. We can do it. Reporter: But this morning, president trump once again attacking the media, tweeting, a very big part of the anger we see today in our society is caused by the purposefully false and inaccurate reporting of the mainstream media that I refer to as fake news. It has gotten so bad and hateful that it is beyond description. Mainstream media must clean up its act fast. White house press secretary Sarah Sanders coming to the president's defense. There's a big difference between comments made and actions taken. The president's condemned violence in all forms, has done that since day one, will continue to do that. But certainly feels that everyone has a role to play. Reporter: In a statement made last night, Jeff Zucker said there is a total and complete lack of understanding at the white house about the seriousness of their continued attack on the media. The president and especially the white house press secretary should understand their words matter. Thus far, they have shown no comprehension of that. As the manhunt continues, copy cats remain a concern. Law enforcement is definitely worried about copy cats and they're also worried that whoever made these bombs probably has some leftover explosive material. That's a public safety issue. Reporter: In New York, a city stands firm in the face of yet another act of terror. This is a city where 8.6 million people live in a practical kind of harmony that's extraordinary. Nothing that's happened in the last day or two has changed that.
This transcript has been automatically generated and may not be 100% accurate.