His communications were conversational and his instructions specific, federal authorities claim.
Here's how to make a pipe bomb, he allegedly wrote. Here's how to make it deadlier, by adding shrapnel dipped in rat poison. And here's where to have it explode -- at a 9/11 commemoration event in Kansas City, Missouri.
None of the above came to be. And the man who federal authorities allege tried to make it happen -- by offering advice online to someone who was actually an FBI informant -- is now behind bars.
Joshua Ryne Goldberg of Orange Park, Florida, has been charged with distribution of information relating to explosive, destructive devices and weapons of mass destruction, U.S. Attorney A. Lee Bentley III of the Middle District of Florida said Thursday in a news release.
Post claimed man had 'a vast network of mujahideen'
According to a criminal complaint, authorities tied the 20-year-old Goldberg to the online pseudonym as "Australi Witness" and "AusWitness," a Muslim living in Australia who was promoting jihad around the world.
The FBI said it became aware of him through Twitter messages under the Australi Witness handle that encouraged attacks "with your weapons, bombs or knives" on the Muhammad Art Exhibit and Contest in Garland, Texas, before they happened in May. Two men did attack, but didn't get into the building after being shot to death by police.
Authorities tied a June post from "Australi Witness" to an ISIS-related website in which he boasted of "inspiring the attacks in Garland" and having "successfully encouraged (two people in Los Angeles and Melbourne, Australia) to carry out jihad in their respective cities."
"Both of these mujahideen will, using guns, shoot up local synagogues when the maximum amount of Jews are praying," the post said. "The entire thing was my idea, and I helped them every step of the way."
He goes on to claim he lives in Perth, Australia, and has "a vast network of mujahideen around the world. And I will continue to inspire and coordinate jihad attacks around the world."
Suspect: I wanted to be hailed as a hero
That's when the FBI confidential source entered the picture by communicating with him through a direct messaging application, the complaint said.
It started in late July, with references to Garland and small talk. By mid-August, the discussions turned to planning an attack -- including Goldberg allegedly sending via Twitter "five website links that contained instructions on how to construct explosives, including pipe bombs and incendiary devices."
The next focus of conversation was where to attack, with "AusWitness" asking if the informant could travel to Kansas City and eventually settling on the Kansas City Stair Climb, a September 13 event in which firefighters honor New York City firefighters killed in the 9/11 terrorist attacks, the complaint said.
A criminal complaint filed in U.S. District Court describes alleged conversations between the informant and the suspect, such as the one below which allegedly occurred on August 20, 2015:
7:03 AusWitness: "Have you decided what kind of attack to carry out on 9/11, akhi? I was thinking a bombing."
7:06 AusWitness: "We could make pipe bombs and detonate them at a large public event.
7:06 CHS: "Yes I'm leaning towards that too. I've been getting excited about this. I've been having trouble with the planners in the dawlah who want me to just do a gun attack. But that doesn't seem big enough to bring true glory to Allah. Look at Chattanoogo the kuff have already forgotten."
7:07 AusWitness: "Exactly brother. It needs to be big. Do you live in NYC? I'm in Perth. There are lots of places to target here."
7:07 CHS: "Do you know the directions you gave me work? I've never made a bomb before lol sorry"
7:08 AusWitness: "They work, akhi. But a pressure cooker bomb might be even better. Let me ask one of my brothers in the dawlah for instructions."
7:10 CHS: "Ok, ahki"
7:13 AusWitness: "What city are you in akhi? We need to find the best place to place the explosive."
7:13 CHS: "I'm in the Midwest the closest place is Kansas City if you're familiar. But I can travel I'm just a student."
7:14 AusWitness: "Alright so will you be able to drive to Kansas City to carry out the attack?"
7:14 CHS: "Yes Easily"
Australi Witness urged the FBI source to put nails, glass and metal into the bomb, according to the FBI-authored complaint. He instructed the FBI source "to dip the screws and other shrapnel in rat poison in order to inflict more casualties," the complaint states.
"I haven't made one before, but I've studied how to make them," AusWitness said in one piece of dialogue quoted in the complaint. "Get FAR away from the bomb, brother. There's going to be chaos when it goes off. Shrapnel, blood and panicking kuffar will be everywhere." (Kuffar is a derogatory term used to describe non-Muslims).
Authorities eventually managed to tie the posts to an IP address in Goldberg's Florida home.
When they went there on September 9 on a search warrant, the complaint states that he waived his rights and spoke to law enforcement -- initially denying he had distributed bomb-making info online or had any role in a terror plot.
But then Goldberg allegedly changed his tune, admitting that he'd used the online names AusSecret, AusWitness and Australia Witness, he'd called for an attack in Garland and posted the long message that referred to his "network of mujahideen."
As to the Kansas City bomb plot, the accused allegedly made "varying statements," according to the complaint.
"In general, ... Goldberg claimed that he intended for the individual to either kill himself creating the bomb or, if not, that he intended to alert law enforcement just prior to the individual detonating the bomb, (so Goldberg would) receive credit for stopping the attack," the complaint states.
Goldberg confessed when agents raided his home, the complaint said. He said he planned to notify authorities before the bomb was detonated so he could be a hero, the complaint said.
If convicted, he could be sentenced to 20 years in prison.