Package bomb suspect Cesar Sayoc's van contained possible bomb-making materials: Sources Cesar Sayoc, 56, is the suspect in the suspected mail bombing spree this week.

The van belonging to the suspect in a series of bombs mailed to prominent Democratic leaders and the news network CNN contained a printer, stamps, paper, an unidentified powder and soldering equipment, pointing at least preliminarily to the vehicle being a possible location for the assembly of the alleged improvised explosive devices (IEDs), according to two officials briefed on the probe.

The discovery and cataloging of the van's contents is a significant step forward for investigators. Just 24 hours ago, they were actively hunting for the location where he had built the devices, fearing they might find more. Investigators continue trying to determine whether the suspect had any accomplices.

A post from Oct. 3 believed to have been written by the suspect, 56-year-old Aventura resident Cesar Sayoc, reads, "See u soon" -- tagging former U.S. Attorney General Eric Holder. The tweet criticized Holder for covering up the killing of Border Patrol agent Brian Terry earlier this year.

Another tweet from June 27 directed toward Rep. Maxine Waters reads "see you soon" -- misspelling her name and Twitter handle. The account also featured tweets to Rep. Joe Kennedy III, actor Jim Carrey and Bill and Hillary Clinton.

Twitter has suspended the account, but the social media company declined to comment on the ongoing investigation to ABC News. Facebook also removed the accounts believed to belong to Sayoc.

"There is absolutely no place on our platforms for people who attempt such horrendous acts," Facebook officials said in a statement to ABC News. "We have found and immediately removed the suspect's accounts on Facebook and Instagram. We will also continue to remove content that praises or supports the bombing attempt or the suspect as soon as we're aware."

Sayoc has an extensive criminal history, a law enforcement source said, and has been arrested at least eight times in Florida alone, court documents show. The arrests range from misdemeanor giving false information to get a refund to grand theft auto.

One of the arrests took place in 2002 when he pleaded guilty for a charge listed as "threaten discharge destructive device."

In that incident, Sayoc reportedly called Florida Power & Light (FPL) and "threatened to blow up FPL and that 'it would be worse than September 11th," court documents state.

He also "threatened that something would happen to the FPL representative if they cut his electricity."

Sayoc was sentenced to probation for that charge, records show.

His attorney at the time, Ronald Lowy, told "Good Morning America" Saturday that Sayoc was "charismatic" but also seemed "very immature" and exhibited "childish behavior."

Sayoc "just seemed like someone who was emotionally out of control," Lowy said.

Lowy added that Sayoc's condition worsened as became estranged from his family. And Lowy said Sayoc had been looking to fill a void after his father "abandoned" him during his childhood and returned to his native Philippines.

"He apparently [missed] the father figure, and he found it in 2016," Lowy said, referring to then-candidate Donald Trump.

Sayoc served as DJ at Ultra Gentleman's Club in West Palm Beach, Florida, as recently as Thursday from noon to 9 p.m., just hours before his arrest. He left the club and went to the gym after his shift, before returning to collect his tips from earlier and hang out after midnight.

In 2014, he was a “road manager for a variety of traveling male revue shows Chippendales International Gold Productions, Cesar Palace Royale Burlesque Show" and he was involved with "the sale of merchandise, coordinating bookings and supervising operations," the court documents report.

Chippendales denied that Sayoc was ever affiliated with the company.

"Cesar Altieri or Cesar Sayoc, was, and has never been affiliated in any way with Chippendales USA, LLC," the company said in a statement.

Sayoc filed for bankruptcy in 2012, when he was 50 years old, and the petition stated that he lived with his mother and had no furniture.

He was taken into custody in Florida shortly before noon Friday for allegedly carrying out a mail bombing campaign that gripped the nation. The night before the arrest, around 10:20 p.m., Sayoc had checked into a South Florida gym where he is a member, sources told ABC News.

His capture comes after 14 package bombs were intercepted over the course of the week, with targets including prominent Democrats like former President Barack Obama and former Secretary of State Hillary Clinton.

Multiple law enforcement sources told ABC News that Sayoc was tracked using a cellphone. He was arrested at an AutoZone in the town of Plantation at around 10:30 a.m. Friday. Authorities have recovered a cell phone, a laptop computer and other electronic devices in connection from Sayoc.

Sayoc appeared unperturbed when he was apprehended and led into a police vehicle, witness Paul Smith told ABC Miami affiliate WPLG.

"It almost seemed like he knew he was going to get caught soon and that he was expecting it," Smith said. "He was in handcuffs, and he was calmly escorted to the vehicle. I saw him get in, no problem. And he just had that look of, 'OK. It's over.'"

Sayoc's residence is listed as his mother's home in Aventura, but he was, for a time, living in the white van covered in stickers of President Donald Trump, which is now being investigated.

A relative of his told ABC News that the family is in shock.

"We're in shock -- just shock," the relative said. "It's all very, very hard to process. It's just a crazy thing."

A former employer of Sayoc's told ABC News that he was a model employee but held offensive views. She described two different sides of Sayoc, one that was polite and professional and another that sympathized with white supremacist beliefs and harbored hateful thoughts about the LGBT community.

"He hated the Obamas. He called him a monkey and the n-word," said Debra Gureghian, who was Sayoc's manager at New River Pizza and Fresh Kitchen, where he worked as a delivery driver. "He hated Hillary Clinton. He called her a lesbian. ... And Adolf Hitler, he loved. Adolf Hitler he couldn't say enough about."

Gureghian said she is a lesbian and endured verbal abuse from Sayoc because of it, but tried to treat him with kindness because "there is enough hatred in this world."

Daniel Lurvey, Sayoc's former attorney who represented him in his grand theft and petty theft charges in Miami-Dade and Broward Counties, also expressed surprise that he was arrested for the string of suspicious packages, describing him as "a gentleman" with "no political agenda."

"He’s as regular, non-political as can be," Lurvey told ABC News, adding also that he is "somewhat gregarious and friendly."

Another one of Sayoc's former attorneys, Lowy told ABC News that Sayoc's mother is a committed Democrat and that his alleged behavior is inconsistent with her political views.

The case against Sayoc will be handled by federal prosecutors in the Southern District of New York, according to a senior law enforcement official.

He is scheduled to appear first in the jurisdiction in which he was arrested, the Southern District of Florida, on Monday afternoon.

Attorney General Jeff Sessions announced Friday afternoon that Sayoc was charged with five federal crimes: interstate transportation of an explosive, illegal mailing of explosives, threats against former presidents and certain other persons, threatening interstate communications, and assaulting current and former federal officers.

In total, those charges could lead to 48 years in prison.

"This is a law and order administration. We will not tolerate such lawlessness, especially not political violence," Sessions said.

Here is the charging document:

Sayoc-181026 by ABC News Politics on Scribd