In the most recent case, Sebastian Senakiewicz, 24, is charged with with falsely making a terrorist threat. He also was charged with conspiracy and unlawful use of a weapon after a raid on the Northwest Side home in which he was staying.
Authorities say he planned to build a Molotov cocktail and use it during the meeting of world leaders.
According to authorities, Senakiewicz was arrested at approximately 4:15 p.m. Thursday after police serached the home for "explosive or incendiary devices," bomb triggers, documents on making explosives, and "maps, diagrams, and drawings of the Chicago Metropolitan area and any and all objects which could be used as a disguise or a container for an explosive or incendiary device."
Prosecutors say Senakiewicz told others he is a member of the "Black Bloc" anarchist group. Known as Sabi, the 24 year old Northwest Side resident allegedly was planning to use homemade explosives during the NATO summit.
"Sabi told others he had changed the detonator of his explosives and claimed the explosives were located in hallowed out Harry Potter book at his residence," said assistant state's attorney Jack Blakey.
"Senakiewicz made statements during the course of the ongoing NATO investigation that he was in possession of explosives," a law enforcement source told the ABC7 I-Team but the source added "no explosives ever recovered" in the Senakiewicz case.
The search warrant on the home in the 3600-block of North Odel was executed by 16th District police.
Senakiewicz was charged Saturday afternoon. He had only been staying at the Odell residence for a few weeks. A previous address listed a residence in Harwood Heights.
In an unrealated case, the three other protesters were charged with plotting terrorists acts, including attacks on police, President Obama's campaign headquarters, Chicago Mayor Rahm Emanuel's home and other government facilities. They were charged Saturday, as well, and a judge ordered them held on $1.5 million bond.
Those men -- Brian Church, Jared Chase and Brent Betterly -- were taken into custody after an apartment raid in Bridgeport last Wednesday. Court records say officers found weapons, Molotov cocktails in the process of being made, plans for pipe bombs, a Chicago-area map, an assault vest and more.
The Bridgeport arrests were based on at least two police "plants" according to detectives. "For safety and security reasons," a top law enforcement official says they will not disclose whether the undercover operatives were actually police officers posing as radicals or were activists that agreed to cooperate with authorities
All three are from out of state. They are facing Illinois' first terrorism charges.
State Attorney's Anita Alvarez and Chicago Police Supt. Garry McCarthy talked about the case Saturday afternoon.
"When the information was obtained by the police department, and we began working with them, it was a pro-active investigation. We use every legal tool we had available to us," Alvarez said. "I believe that all the procedures we followed were proper. We got a search warrant. Despite what is been reported, we did have a search warrant that was signed by the judge. The police department and the FBI executed it."
"It is important to distinguish between these and the peaceful protesters. If you look at the way we interact with the protesters, it is different because we understand that distinction," McCarthy said.
At least of the two charged in the Bridgeport raid should appear in court next Tuesday.
"These 2 men were targeted without a doubt for their political beliefs," said Sarah Gelsomino, of the National Lawyers Guild.
Defense lawyers claim two police informants -- a male and female known as "moe and gloves" -- provided information to investigators on all the cases. The Natioanl Lawayers Guild accuses these informants of manufacturing facts to police.
Senakawicz appeared in Central Bond Court Sunday, along with another suspect in a third case involving a possible NATO-related attack. That suspect, identified as 28-year-old Mark "Migs" Neiweem, was arrested on explosives charges in the 1200-block of South Union near a Western Union Office last week.
Neiweem is believed to be from Chicago.
As the I-Team reported on Friday, Neiweem is a self-professed anarchist who is a member of the Anarchist Black Cross and frequents their chat rooms. In 2010, he was charged with punching a Chicago police officers in the face, a case for which he is now on probation.
According to the Cook County state's attorney's office, Neiweem is charged with attempted possession of explosives or incendiary devices.
"Neiweem made statements during the course of the NATO investigation indicating that he knew how to make a pipe bomb and requesting the materials to make a pipe bomb. No pipe bomb ever made he is being charged based on the statements that he made," said a law enforcement source familiar with the case.
Even as President Obama, heads of state and foreign ministers arrived in Chicago, police and the U.S. Secret Service were concerned about the plans, plots and schemes that might still be hidden, said several counter-terror investigators who asked not to be quoted by name.
ABC7's Sarah Schulte contributed to this report.