A Florida college student described as an “online troll” responsible for “hoax events” is in custody after allegedly instructing an FBI informant to place a pressure cooker bomb at an event commemorating the September 11 attacks, the Justice Department announced on Thursday.

According to charging documents, officials first became aware of 20-year-old Joshua Ryne Goldberg in June when he claimed online to have “encouraged” the attack on an anti-Muslim cartoon contest in Texas earlier this year. From WTLV:

Between July and September, Goldberg had been in contact online with an individual, who—unbeknownst to Goldberg—was actually an informant. Goldberg had allegedly provided the individual with details on how to construct a bomb and instructed him to fashion a pressure cooker bomb and fill it with nails, metal and other shrapnel dipped in rat poison.

According to the complaint, Goldberg directed the individual to place the bomb at a memorial in Kansas City, Mo. that was commemorating the Sept. 11, 2001 terrorist attacks.

“Put the backpack near the crowd,’’ Goldberg allegedly told the informant. “But make sure it’s in a place where the (police) won’t think anything of it.’’

After his arrest, authorities say Goldberg claimed he planned to either encourage the informant to kill himself prior to the bombing or alert law enforcement and get credit for stopping the attack.

On Friday, Australian Federal Police sent the FBI an interview with a source that said Goldberg was an “online troll” and “proponent of radical free speech” who carried out hoaxes by adopting multiple personalities on the internet.

In one IRC conversation, Goldberg allegedly said, “These guys are pussy keyboard warriors” when asked if he was worried about jihadists actually killing someone at his command.

In another, Goldberg allegedly asked the source, “You’re not gonna turn me into the feds for pretending to be ISIS, are you?”

Goldberg has now been charged with distributing information relating to explosives, destructive devices and weapons of mass destruction. If convicted, he faces up to 20 years in prison.

[Image via AP Images]