When Joshua Goldberg wasn’t posing as an Islamic radical, he was pretending to be a white supremacist—and is accused of impersonating a Jewish lawyer.

Goldberg had several online personas: an Islamic radical who was popular in ISIS social media; a white supremacist on hate site Daily Stormer; a radical free-speech advocate on Q&A site Ask.fm and and a blog. Goldberg is also accused of being behind a Times of Israel blog post that called Palestinians “subhuman.”

Goldberg’s trolling turned serious when he was arrested Thursday by the FBI on the grounds that he told a would-be terrorist how to build a bomb meant for a 9/11 anniversary event in Kansas City, Missouri.

The 20-year-old, who lived at home with his parents and was described as a recluse by neighbors, was a prolific tweeter through accounts with various permutations of the name @auswitness. Goldberg was so successful at his game that he was even retweeted by one of the pro-ISIS gunman who attacked a “Draw Muhammad” event in Garland, Texas, last May, according to the FBI.

“You might know me for inspiring the attacks in Garland, Texas, where two mujahideen entered an event mocking the Prophet Muhammad (PBUH) with intent to slaughter the kuffar in it,” he boasted as Australi Witness in a post on Justpaste.it. “All who defame the Prophet (PBUH) must be crushed.”

“Australi Witness” claimed to have his own alter ego as a “moderate” Muslim who worked for major nonprofit groups like Amnesty International by day.

But it was Australi Witness’s role in helping a confidential FBI informant plan an attack on the anniversary of 9/11 that brought Goldberg’s trolling to an end. (The complaint alleges that Goldberg confessed “in substance” to being the voice behind Australi Witness and affiliated accounts.)

“You might know me for inspiring the attacks in Garland, Texas.”

“Hopefully there will be some jihad on the anniversary of 9/11,” he wrote to the FBI informant through a direct messaging app as AusWitness on August 17, according to a criminal complaint.

His wish seemed to come true when the online friend proposed carrying out an attack. The friend said he lived near Kansas City and that a memorial in honor of firefighters who died on 9/11 might be the perfect target.

“Where do you think would be best near the firefighters or the crowd?” the informant asked.

Goldberg egged him on.

“Good thinking, akhi [brother]. Put the backpack near the crowd,” he allegedly wrote, adding that nails in the bomb should be soaked in rat poison to maximize their lethality.

Feds say Goldberg didn’t deny pushing the man toward a real-life attack in interviews with them. Goldberg even allegedly confessed to it all, telling the FBI he believed that his instructions would work, that the other person was serious about making a bomb and “would actually attempt to use them to kill injure persons.”

Then Goldberg backtracked, according to the FBI, saying he hoped the wannabe terrorist would blow himself up making the bomb. If not, Goldberg said he would have called police just before the attack took place and then been hailed as a hero.

The FBI says in the complaint that it wasn’t aware that Goldberg was not a real ISIS sympathizer when they began the investigation.

Goldberg, who comes from a Jewish family, had Australi Witness spout a special kind of rage when discussing Jews.

“The Jews are the worst enemies of Allah (SWT). When Islam conquers Australia, every single Jew will be slaughtered like the filthy cockroaches that they are,” he wrote on JustPaste.it.

Goldberg as Australi Witness also threatened attacks on synagogues in Melbourne and Los Angeles on JustPaste.it and on 8Chan’s Islamic State page.

He also had recurring obsessions with certain people and ideas, attacking them with one persona while praising them with another.

Posing as “Michael Slay” on white supremacist site Daily Stormer, he viciously attacked an Australian Muslim activist Mariam Veiszadeh, calling her a “Moslem pig.” Yet Goldberg praised Veiszadeh as Australi Witness, calling her his “biggest inspiration.” Yet another alleged online identity, MoonMetropolis, cheered grotesque caricatures of Veiszadeh.

In articles published under the Moon Metropolis alias and under Goldberg’s own name on Thought Catalog, he expresses the opinions of a free-speech fundamentalist.

“Nothing that anyone could possibly say could ever be worse than a law preventing them from saying it,” he wrote. “If you expressed the opinion that I should be killed, I would still defend your right to say that.”

On Thought Catalog, Goldberg wrote “that neo-Nazis tend to look positively civil and rational when compared to SJWs [social justice warriors].”

Goldberg’s Australi Witness alter ego has also been tied to a hoax blog post on the Times of Israel’s website that called Palestinians “worthless subhuman beasts and vermin” who have no right to live. It was published under Australian lawyer Josh Bornstein’s name. (The post was retracted and the news outlet published an apology.)

One site noted in May that Australi Witness’s Twitter account was obsessed with hounding Bornstein—re-upping the fake blog post and asking how to find Bornstein’s name. “Michael Slay” also wrote pieces about Bornstein on the Daily Stormer site, but all of his “contributions” have now been taken down on suspicion that he was behind the Bornstein hoax. Goldberg has not admitted to writing those articles, but the site claims he contacted them with an email tied to Goldberg in the criminal complaint.

Goldberg’s father was reportedly broadsided by the charges against his son.

“You guys know more than we do at this point,” he told the media, tersely.

Few online trolls ever pay for what they do, but the charge against Goldberg carries a maximum penalty of 20 years in federal prison.

(http://www.autoadmit.com/thread.php?thread_id=2987386&forum_id=2#28739322)