PLANTATION, Fla. (Reuters) - The man suspected of mailing at least 14 pipe bombs to some of U.S. President Donald Trump’s leading critics was arrested on Friday in Florida on federal charges in a case echoing the rancor of one of the most toxic election campaigns in decades.

Cesar Sayoc, 56, a part-time pizza deliveryman, grocery worker and former stripper once charged with threatening to bomb an electric company in a billing dispute, was taken into custody by federal agents outside an auto parts store in Plantation, Florida, near Miami as helicopters flew overhead.

Authorities also seized a white van that Sayoc appeared to have used as his dwelling, its windows plastered with pro-Trump stickers, the slogan “CNN SUCKS” and images of Democratic leaders with red cross-hairs over their faces.

Fingerprint and DNA evidence helped identify the suspect, but his arrest did not necessarily end the threat, Federal Bureau of Investigation Director Christopher Wray warned at a news conference.

“There may be other packages in transit now and other packages on the way,” Wray said.

One federal law enforcement source told Reuters that authorities were investigating whether other individuals were involved and did not rule out further arrests.

Sayoc’s arrest followed an intense four-day manhunt sparked by the discovery of bombs concealed in packages addressed to such leading Democratic figures as former U.S. President Barack Obama and former first lady and Secretary of State Hillary Clinton, whom Trump defeated in the 2016 presidential race.

Some of the parcels also contained photographs of the intended recipients marked with a red X, according to a criminal complaint in Manhattan federal court.

The complaint accused Sayoc of sending 13 bombs to 11 individuals, starting with billionaire Democratic donor George Soros. A package surfaced on Monday near his home in Katonah, New York.

A 14th package was found on Friday at a post office outside San Francisco addressed to another wealthy contributor to the Democratic Party and liberal causes, Tom Steyer.

The bombs were sent in manila envelopes lined with bubble wrap and consisted of plastic 6-inch pipes packed with explosive material and wired to small clocks and batteries, the complaint said.

Wray said investigators had yet to determine whether the bombs were actually “functional,” but added that the devices could be dangerous “if subjected to the right combination of heat or shock or friction.”

All were sent through the U.S. Postal Service system and intercepted before reaching their intended targets without exploding. No one has been hurt.

But the bombs have heightened tensions during the closing days of a highly contentious campaign ahead of the Nov. 6 elections in which Democrats are battling to seize control of Congress now held by Trump’s Republican Party.

Wray said fingerprints on one of two packages sent to U.S. Representative Maxine Waters, a Los Angeles Democrat frequently disparaged by Trump as “low-IQ Maxine,” belonged to Sayoc. The complaint also cited a “possible DNA” link between samples taken from two of the bombs and a sample previously collected from Sayoc.

‘POLITICAL VIOLENCE’

Sayoc was charged with five felony counts, including interstate transportation and illegal mailing of explosives, threatening a former president, making threatening interstate communications and assaulting federal officers.

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If convicted, Sayoc could be sentenced up to 48 years in prison, officials said.

“We will not tolerate such lawlessness, especially political violence,” Attorney General Jeff Sessions said at a press conference.

Announcing the arrest to a cheering audience at the White House, Trump said, “We must never allow political violence to take root in America - cannot let it happen,” Trump said. “And I’m committed to doing everything in my power as president to stop it and to stop it now.”

A native of New York City’s Brooklyn borough and a registered Republican, Sayoc made his political views evident on social media. In Facebook and Twitter posts, he railed against Democrats, Muslims and liberals, including an anti-Soros tweet two days before a bomb showed up at the financier’s home.

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The Arizona Republic newspaper reported that Sayoc threatened Republican U.S. Senator Jeff Flake, one of the few Republicans in Congress openly critical of Trump, in a pair of Oct. 1 Twitter posts consisting of violent imagery and a photo of Flake’s Arizona home, with the message, “... very nice house Jeff a lot entrances.”

Public records showed numerous arrests over the years for domestic violence, theft and other charges, including the alleged bomb threat against a utility company.

Sayoc was expected to be held at the Federal Detention Center in downtown Miami and make his first appearance before a judge on Monday, according to former Assistant U.S. Attorney David Weinstein.

A public defender listed as Sayoc’s attorney of record in New York, Sarah Baumgartel, could not immediately be reached for comment.

Ron Lowy, a former lawyer for Sayoc who now represents his family, told CNN he believed Sayoc was left emotionally scarred as a boy when his father left the home, developing an identity crisis in which he ultimately embraced Trump as a kind of father figure.

“It’s my opinion that he was attracted to the Trump formula of reaching out, Trump reaching out to these types of outsiders - people who don’t fit in, people who are angry at America, telling them that they have a place at the table, telling them that it’s OK to get angry,” Lowy said.

‘STOP THE RANCOR’

All the individuals targeted by the packages Sayoc is accused of sending have been outspoken critics of Trump and his administration, foils for the president and his right-wing supporters or both.

Among intended recipients earlier in the week were former Vice President Joe Biden, former Attorney General Eric Holder, actor Robert De Niro and former CIA director John Brennan, whose security clearance Trump revoked after Brennan lambasted Trump’s Russia summit performance as “nothing short of treasonous.” His package was delivered to the Manhattan bureau of CNN, where he had served as an on-air analyst.

On Friday, packages surfaced for Democratic U.S. Senator Cory Booker of New Jersey, former U.S. Director of National Intelligence James Clapper and Democratic U.S. Senator Kamala Harris of California.

The episode has sparked an outcry from Trump’s critics charging that his inflammatory rhetoric against perceived enemies among Democrats and the press has fostered a climate ripe for politically motivated violence.

“If we don’t stop this political mania, this fervor, rancor, hatred, you’ll see this again and again and again,” New York Governor Andrew Cuomo told MSNBC. “...It starts with the president.”

Trump’s supporters have accused Democrats of unfairly suggesting that the president was to blame for the bomb scares, and Trump himself accused the press of using coverage of the investigation to score political points against him.

After first calling for unity at the White House event, Trump lamented partisan attacks against him and again pointed at the media.

“I get attacked all the time ... I can do the greatest thing for our country, and on the networks and on different things it will show bad,” he told the crowd, acknowledging an attendee who shouted “fake news.”