Sayoc Jr.'s detention and removal hearing is scheduled for Friday morning.
The latest development comes hours after FBI officials discovered yet another suspicious package in Atlanta, Georgia, with the intended recipient being CNN. It has also been reported that Sayoc Jr. had a list of more than 100 people whom he intended to target.
According to the Sun-Sentinel, Sayoc Jr., who sat by himself at the back of the jury box, spoke just a few words when responding to US Magistrate Judge Edwin Torres. "Sayoc looked calm, almost relaxed," the report states.
On Friday, after reports surfaced that law enforcement officials had arrested Sayoc Jr., US Attorney General Jeff Sessions announced that the Florida resident had been charged with 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.
If convicted, the 56-year-old suspect will spend up to 48 years in prison. He will be tried in the US Southern District of New York.
Sayoc Jr.'s packages were sent to the likes of billionaire Democratic donor George Soros, former Secretary of State Hillary Clinton, former US President Barack Obama, former US Vice President Joe Biden and former CIA Director John Brennan via CNN, among others.
The packages, which began turning up on October 22, each contained roughly six inches of PVC pipe, wiring, a small clock and what FBI Director Chris Wray has described as "energetic material."