A wave of pipe bombs was sent to prominent Democratic politicians, including former President Barack Obama and former Secretary of State Hillary Clinton, sparking an intense investigation on Wednesday into whether a bomber is going after targets that have often been the subject of right-wing ire.
CNN also received a similar bomb, addressed to Mr. Obama’s C.I.A. director John Brennan, touching off a mass evacuation of the Time Warner Center in Midtown Manhattan, where the network is located.
A law enforcement official said the devices were similar to one found Monday at the home of George Soros, the billionaire philanthropist and liberal donor.
None of the devices harmed anyone. Law enforcement officials said they were investigating whether all the devices were sent by the same person or persons.
Mrs. Clinton, Mr. Obama, Mr. Soros and CNN have all figured prominently in conservative political attacks — many of which have been led by President Trump. He has often referred to major news organizations as “the enemy of the people,” and has had a particular animus for CNN.
The device sent to CNN was in a manila envelope addressed to Mr. Brennan, a harsh critic of Mr. Trump. The president revoked Mr. Brennan’s security clearance in what was seen as an act of retribution.
The envelope’s return address bore the name of Debbie Wasserman Schultz, a Florida congresswoman and a former Democratic National Committee chairwoman, according to a person who saw a photograph of the envelope. The device sent to Mr. Soros was in a similar envelope also with a printed return address label with her name.
A fifth device apparently intended for the man who served as Mr. Obama’s attorney general, Eric H. Holder Jr., was misaddressed and because Ms. Wasserman Schultz’s name was on the return address, it was ultimately delivered to her district office in Florida, a law enforcement official said.
Then later, on Wednesday afternoon, another package addressed to another Democrat, Representative Maxine Waters of California, was intercepted at a Congressional mail facility, according to a Democratic official briefed on the investigation. In recent months, Ms. Waters has been a frequent target of Mr. Trump.
The bomb sent to CNN’s offices was delivered by courier, though it had half-a-dozen first class postage stamps on it, a law enforcement official said. Investigators believe the bomb sent to Mr. Soros’s home was dropped off in his mailbox.
It was not immediately clear how the other packages were delivered.
Gov. Andrew M. Cuomo said at a news conference that his office in Manhattan had also received a package, but a law enforcement official later said it was unrelated to the bombs.
On Wednesday afternoon, President Trump addressed the attempted bombings, telling reporters: “Acts or threats of political violence of any kind have no place in the United States of America.”
The bomb sent to CNN was in an envelope addressed to John Brennan, former President Barack Obama’s C.I.A. director.
In an earlier statement, the White House said “anyone responsible will be held accountable to the fullest extent of the law.”
Mrs. Clinton, in an address to a crowd of about 200 Democratic donors in Florida on Wednesday, said: “It is a troubling time, isn’t it, and it’s a time of deep divisions and we have to do everything we can to bring our country together.”
In Manhattan, Mayor Bill de Blasio called the attempted bombings “an effort to terrorize” and vowed the city’s residents “won’t allow terrorism to change us.”
“This is a very painful time in our nation,” the mayor said. “It’s a time when people are feeling a lot of hatred in the air and incidents like this exacerbate that feeling.”
The first inkling that there might be a serial bomber came Wednesday morning when the Secret Service revealed that it had “intercepted two suspicious packages addressed to Secret Service protectees,” who were Mrs. Clinton and Mr. Obama.
The device addressed to Mrs. Clinton in Westchester County, north of New York City, was found late on Tuesday by a Secret Service employee who screens mail for her, the statement said. The package addressed to Mr. Obama was intercepted early on Wednesday by Secret Service personnel in Washington.
Shortly after the Secret Service made that announcement, the Time Warner Center, a major office complex, was evacuated when a similar device was discovered to have been sent to CNN’s offices there.
A senior law enforcement official in New York, describing the bomb sent to CNN, said it was intercepted in the basement mailroom and resembled the others: “Same package. Same device.”
That device was constructed from a length of pipe a little longer than six inches and wrapped in black tape with what appeared to be epoxy on the ends, according to a person who had seen a photograph of it. What could be a timer was attached to the side of the pipe and wires were visible at both ends. Like the bomb sent to Mr. Soros’s home, the envelope it arrived in was roughly 5-by-8 inches and had a printed white address label and half a dozen first-class postage stamps affixed to the outside.
On Wednesday afternoon, New York City’s police commissioner, James P. O’Neill, said the CNN bomb was “a live explosive device” and that it would be rendered harmless and sent to the F.B.I. to be analyzed. The package that contained the device also included white powder that the police were testing to determine if it is toxic, he said.
One of the envelopes sent out had several stamps on it, more postage than it needed to be delivered, according to a former law enforcement official briefed on the investigation. The extra postage led investigators to believe that the person who mailed it wanted to avoid going to a post office to buy the correct postage — a step to evade detection, the official said.
The statement from the Secret Service also said: “The packages were immediately identified during routine mail screening procedures as potential explosive devices and were appropriately handled as such. The protectees did not receive the packages nor were they at risk of receiving them.”
The agency also said it had “initiated a full scope criminal investigation that will leverage all available federal, state, and local resources to determine the source of the packages and identify those responsible.”
Mr. Soros’s home is in Katonah, a hamlet in Westchester. That device was constructed from a length of pipe about six inches long filled with explosive powder, and it was “proactively detonated” by bomb squad technicians, according to one of the officials, all of whom were briefed on the investigation. It was rigged with a detonator, and it could have maimed or possibly killed someone had it exploded near them.
A federal official said law enforcement agencies were closely examining possible ties between the packages and the one sent to Mr. Soros, who has come under fierce criticism from conservatives and conspiracy theorists. The connection was being “strongly considered,” said the federal law enforcement official, who would only speak on condition of anonymity because the investigations were ongoing.
While the investigation is in its earliest stages, the recovery on Wednesday of the devices and the envelopes that contained them could potentially provide federal agents with a trove of leads and evidence. It could allow them to assess the sophistication of, and care taken, by the person or persons who built and mailed the bombs.
Bomb technicians will likely seek to defuse the devices and try to determine where their components were purchased or the bombs were made. Evidence technicians may attempt to recover traces of DNA or fingerprints from the components and the envelopes that contained the bombs.
Federal agents with the United States Postal Inspection Service could play an important role in the investigation if any of the packages were delivered through the U.S. mail. They would examine the postage and postmarks and seek to determine where they were mailed from. Investigators could examine surveillance video at post offices and around blue letter boxes where the packages may have been deposited.
It is unclear where exactly the package addressed to Mrs. Clinton was sent. A security guard at the Clinton Foundation’s Midtown Manhattan offices said the explosive device was addressed to Mrs. Clinton’s home in Westchester, not her offices.
The news of the devices set off a small wave of false reports. Some media outlets reported that a similar device had been addressed to President Trump at the White House, until the Secret Service debunked the account.
Early this month, federal authorities said they intercepted multiple packages suspected of containing the lethal substance ricin, addressed to President Trump and at least two top Pentagon officials. In February, an envelope containing a white powdery substance that investigators later determined was cornstarch was sent to the Manhattan apartment of Donald Trump Jr.’s mother-in-law.