NEW YORK (WABC) -- A man accused of coming at FBI agents with a knife on Staten Island Wednesday morning has been taken into custody.
The agents were investigating an alleged ISIS sympathizer from Queens when they arrived at the house.
21 year old Fareed Mumuni was arrested as the agents searched his home and he lunged at them with a kitchen knife, authorities say.
Court records say he conspired with Munther Omar Saleh, who was arrested Saturday, and others. Law enforcement officials told ABC News additional arrests are possible.
Mumuni's relatives left the courthouse seemingly stunned by the arrest. He stood before the judge in sandals and his traditional Muslim cloak to face the charges.
"He's innocent," said the suspect's uncle Mohammed Afonja. "Do you think if he pull a knife you think he'd be alive? If he pull a knife, what do you think happen? You'd be shot dead there in that building."
But Mumuni has apparently been under surveillance for some time, a friend of Saleh, the Flushing man charged earlier this week with plotting an unspecified terrorist attack in New York City.
In court papers Wednesday, prosecutors claimed, "Mumuni espouses violent jihadist beliefs and is a fervent supporter of (ISIS)." That he, "made efforts to participate in or support a terrorist attack in the New York metropolitan area or elsewhere on behalf of (ISIS)."
And during the search of his home, he "repeatedly attempted to stab an FBI Special Agent with a large kitchen knife."
"His beliefs right now, he's a Muslim. Other than the allegations, it's way too early in the case to be commenting on the accuracy or reliability of the allegations," said Mumuni's attorney Anthony Ricco. "This is just a felony complaint. We're very early in the case, got a long road to go."
Saleh, a 20-year-old college student from Queens, is charged with planning attacks in the metropolitan area on behalf of ISIS.
He appeared in federal court Saturday following a three month federal investigation.
Saleh conducted online searches on building explosives and was eluding law enforcement, authorities say. He was arrested earlier this month near the Whitestone Bridge.
According to investigators, he expressed interest to a confidential informant in conducting ISIS-style jihad in the New York metropolitan area.
Saleh thought al-Qaeda was getting soft and was "making efforts to prepare an explosive device for detonation" in New York, according to a criminal complaint unsealed Tuesday.
According to the federal complaint, it was two times back in March that Port Authority police spotted Saleh crossing the George Washington Bridge suspiciously, first, with a lantern, then simply scouting around.
But the federal government was well aware of his troubling activities.
On Sept. 10, 2014, Saleh tweeted, "I fear AQ", meaning Al Qaeda, "could be getting too moderate".
The complaint also alleges that Saleh tweeted his support of the recent terrorist attack in Garland, Texas, in which 2 suspects fired at a cartoon convention where pictures of the Prophet Muhammed were depicted.
He is a U.S. citizen, and an aeronautics student from Queens studying electrical circuitry.
In the complaint, authorities cite his research on the Internet, including investigating assault rifles and body armor, pressure cooker bombs, propane, knives, ammo and crossbows.
They also say he researched security footage from the Columbine High School massacre in 1999 and New York City landmarks, and that he viewed an article called, "What Does Islam Say About Killing An Innocent Person?"
Early Saturday morning on 20th Avenue near the Whitestone Expressway, Saleh lunged at law enforcement shortly before his arrest, police said. Saleh was arrested Saturday when he was seen driving on the Whitestone Expressway. Court records say he "took several steps" toward an unmarked police vehicle and then began to run toward law enforcement officers before he was detained.
Saleh was accused of being a "fervent supporter" of ISIS and offering to translate Islamic State propaganda into English. He was tracked through his online activities.
The FBI said Saleh told a confidential informant he was "in NY and trying to do an Op." Instructions for pressure cooker bomb making were found on his computer along with images of New York City landmarks and tourist attractions, what court records called "potential targets for a terrorist attack."
Man charged with lunging at FBI agents with knife during terrorism probe on Staten Island