Prosecutors on Monday filed federal hate crime charges against the 37-year-old man accused of storming a Hanukkah celebration at a rabbi's home in Monsey, New York, with a machete and wounding five people.

Grafton Thomas, of Greenwood Lake, pleaded not guilty Sunday to five counts of attempted murder and one count of burglary. On Monday, he was charged in the Southern District of New York with five counts of obstruction of free exercise of religious beliefs involving an attempt to kill and use of a dangerous weapon, and resulting in bodily injury.

Thomas is accused of attacking the group observing the seventh night of Hanukkah on Saturday at the home of Rabbi Chaim L. Rottenberg, next to their synagogue. Monsey is an enclave of ultra-Orthodox Jews, about 35 miles from New York City.

When Thomas barged into the rabbi's home, his face was covered with what appeared to be a scarf, according to the criminal complaint. He told the dozens gathered in the home that "no one is leaving."

Thomas was arrested in Harlem about two hours after the 10 p.m. attack.

Authorities later discovered handwritten journals in Thomas’ home that contained anti-Semitic writings. On one page, he had drawn a Star of David and a Swastika, and written about "Nazi culture" and "Adolf Hitler," according to a federal criminal complaint filed Monday.

Thomas wrote in the same journal an apparent reference to the Black Hebrew Israelite movement. Some groups within the movement hold anti-Semitic beliefs, according to the Southern Poverty Law Center.

Investigators also searched Thomas' phone, on which he had allegedly searched for "Why did Hitler hate the Jews" once in November and three times this month. Also in November and December, he searched for German Jewish temples and Zionist temples "near me" or in specific nearby cities and towns.

And on the day of the attack, he clicked on an online article titled: "New York city increased police presence in Jewish neighborhoods after possible anti-Semitic attacks. Here’s what to know."

The victims were hospitalized with wounds including a severed finger, slash wounds and deep lacerations, prosecutors said. At least one of the victims, who suffered a skull fracture, is in serious condition.

Thomas' family said in a statement Sunday night that he has "a long history of mental illness and hospitalizations" and that his attorney, Michael H. Sussman, had been instructed to seek "immediate mental health evaluation of Grafton."

On Monday, Sussman said during a news conference that he would describe Thomas as "mentally ill." He said Thomas had been hospitalized multiple times this year and was on a variety of medications. He was close with his mother, who was concerned about his well-being and often attempted to help him.

Thomas was held without bail at his hearing in federal court.

Sussman said he could not comment on the federal charges because he had not seen the criminal complaint. But he said that in the 75 pages of "rambling notes" discovered in Thomas' home, there was nothing to suggest anti-Semitism.

Saturday's stabbing was the latest violence in a spate of attacks on Jewish gathering places across the nation since late 2018. On Oct. 27 last year, a man opened fire at the Tree of Life synagogue in Pittsburgh, killing 11.

More recently, on Dec. 10, a couple opened fire at a kosher market in Jersey City, New Jersey, killing a police officer and three other people who had been inside. The shooters were killed in the exchange of gunfire with law enforcement officials. At least one of the shooters was identified as a follower of the Black Hebrew Israelite movement.

Condemning the stabbings Monday, the Rev. Al Sharpton said, "If it had been attacks against members of the black community, we would have stood up and spoke out."

"We cannot remain silent as we see a consistent pattern against people based on their faith and based upon who they are," Sharpton said. "You can’t fight hate against you unless you’re willing to fight against hate against everyone else."

On Monday, officials announced that a private security firm would be volunteering resources to help law enforcement monitor Rockland County, where Monsey is located.

"These are all Rocklanders who saw what happened in Rockland and they know what the true heart of this community is. And they are disgusted by what's happened, they are angry about what happened," County Executive Ed Day said. "And they are going to do something to ensure that it doesn't happen again."