A judge ordered a suspected white nationalist from Washington, D.C., held in jail on federal firearms charges, telling him, "Seems like you were planning something."

Jeffrey Clark Jr. pleaded not guilty Friday afternoon.

An FBI affidavit says Clark admitted he was a member of white nationalist groups and told investigators he had contact with the Pittsburgh Tree of Life synagogue shooter on social media, praising him as a hero. The affidavit says Clark connected with Robert Bowers on Gab, a social networking site.

According to the affidavit, Clark openly discussed killing people of the Jewish faith, as well as African Americans. The affidavit said Clark spoke about Bowers, claiming the synagogue shootings were “justified,” because a same-sex “Jewish couple was having an adopted baby circumcised that week.”

Clark's family took his guns and turned him in to authorities, the FBI said.

Clark's attorneys said his posts are First Amendment free speech and he has never before been in legal trouble. They asked for him to be released into the care of his father Friday, but prosecutors called him a danger, referring to him as a bomb. When the judge asked if Clark's father was the person who turned him in, prosecutors said no.

Federal agents said they found threatening messages by Clark on social media, including one calling the October mailed pipe bombs case a "dry run."

Agents said they found body armor, helmets, hollow-point ammunition, a Nazi flag, a noose and a drawing of an individual pointing a rifle at a male figure wearing a yarmulke several items in Clark’s home after his arrest.

Body Armor, Ammo, Nazi Flag Found in DC Home of Suspected White Nationalist'

According to court filings, federal agents investigated Clark and his brother Edward in early November after receiving a tip the two had been heavily involved in the white nationalist movement.

According to prosecutors, “Clark stated that he and his younger brother Edward started to get into firearms following the 2016 election because they believed there was going to be a civil war.”

Clark’s brother committed suicide in D.C. on the same day of the Tree of Life synagogue massacre, court filings say.

Clark faces 11 years in prison if convicted.