His record in the Broward County court system includes numerous criminal charges including theft, possession of drugs that appear to be steroids, and battery over a period of multiple decades. Sayoc was also accused in 1994 of domestic violence by a woman with the same name as his grandmother, who would have been about 80 years old at the time.
Sayoc filed for bankruptcy in 2012, records show. At the time, he was driving a 2001 Chevy Tahoe with 285,000 miles on the odometer, and appeared to have no assets or property of any kind. Atop an almost completely blank page listing all of Sayoc's goods and furnishings, a handwritten note read: "Lives w/ mom, has no furniture."
In his public profile on the career networking site LinkedIn, Sayoc's describes his only work experience as a promoter and "owner, choreographer" for a male burlesque company similar to Chippendales. A criminal defense lawyer who represented Sayoc in a theft case told CNBC that the job description was more akin to a bouncer.
On Twitter, Sayoc was far more active. In most of his posts in October, Sayoc peddled a host of right-wing conspiracy theories and other attacks against Democrats. He levied threats on the platform against CNN, whose office was targeted with a mail bomb on Wednesday, in an Oct. 12 tweet, saying "Hey CNN all BS con job fraud puppets media blocked,Banned,Barred from all of our properties feel lucky make our day. You will just vanish."
He also appeared to repeatedly refer to himself as a member of the Seminole Tribe of Florida — an assertion that the tribe denied in a statement emailed to CNBC. "We can find no evidence that Cesar Altieri, Caesar Altieri, Caesar Altieri Sayoc, Ceasar Altieri Randazzo (Facebook) or Julus Cesar Milan (Twitter) is or was a member or employee of the Seminole Tribe of Florida, or is or was an employee of Seminole Gaming or Hard Rock International. At this time, we cannot verify if he is or was an employee of a vendor company," a spokesman for the tribe said.
In a series of photos and videos tweeted in mid-October, Sayoc appears to have attended at least one of Trump's campaign-style rallies.
Sessions, at a news conference Friday afternoon, gave no specific insight into Sayoc's motivations, but noted that he "appears to be a partisan, but that would be determined by the facts as the case goes forward."
Sayoc is due to make his first court appearance in the case Monday, before a federal judge in Miami.
WATCH: Trump comments on Sayoc arrest