Authorities arrested an Ohio man last week on suspicion of planning an attack on a synagogue in the Toledo area, Justice Department officials said Monday.

Investigators took 21-year-old Damon Joseph, of Holland, Ohio, into custody on Friday to face one count of attempting to provide material support to ISIS, authorities said in a news release.

“He planned to carry out an attack at a Toledo-area synagogue in the name of ISIS and hoped that it would cause fear and result in a maximum number of casualties,” Assistant Attorney General John Demers said.

Joseph caught investigators’ attention earlier in the year while posting photos of knives and firearms on social media, according to authorities. He also posted a photo that had originally been distributed by ISIS’ media wing, Justice Department officials said.

He told undercover agents he was a supporter of ISIS and, in September, made videos that he sent to an undercover agent in the hopes the footage would be used to recruit people to join the militant organization, authorities said.

Several times, he told undercover investigators that he supported “martyrdom operations,” according to investigators.

“In a matter of months, Damon Joseph progressed from radicalized, virtual jihadist to attack planner,” FBI acting special agent in charge Jeff Fortunato said.

On Oct. 30, three days after a man killed 11 people in an attack inside the Tree of Life Congregation Synagogue in Pittsburgh, Joseph expressed admiration for the shooter while speaking with an undercover agent.

“I can see myself carrying out this type of operation inshallah,” he said, according to court records. “They wouldn’t even expect (an attack) in my area…”

Joseph said several times in the intervening weeks that he wanted to participate in an attack on behalf of ISIS and, on Dec. 2, forwarded a plan for his attack to an undercover agent, court records showed. Joseph didn’t consider his plan “a martyrdom operation,” authorities said, because he had a plan for his escape.

Two days later, Joseph told the agent he was choosing between two synagogues to target and that the decision would depend on “which one will have the most people, what time and what day,” court records showed.

“Go big or go home,” Joseph told the undercover agent, officials said.

Joseph met with the agent on Wednesday and provided him with notes about firearms he wanted ahead of the attack, including AR-15s, an AK-47, Glocks and ammunition, court records showed.

He decided on which synagogue he planned to attack Thursday, telling an undercover agent that he “wanted to kill a rabbi,” officials said. The agent later told Joseph that he had the rifles Joseph wanted for the attack -- a pair of AR-15-type weapons.

Authorities arrested Joseph after he took possession of the bag, officials said.

“The charges describe a calculated man fueled by an ideology of hatred and intent on killing innocent people,” said Justin Herdman, U.S. Attorney for the Northern District of Ohio. “This man spent months planning a violent terrorist attack on behalf of ISIS.”

Authorities continue to investigate the case.