The FBI worked with Israeli authorities to arrest an 18-year-old man who covered his face as he appeared briefly in an Israeli court.

A U.S. law enforcement official tells CBS News the man is believed to be responsible for most of the 160-plus bomb threats phoned in to Jewish centers in the U.S., Australia, New Zealand and Canada.

The FBI sent over a dozen personnel and agents to assist in the investigation, CBS News has learned.

The unnamed suspect covers his face in court CBS News

“We’re looking to see the identification of the suspect himself, his profile, what were the motives behind him carrying out those threats,” said Israeli Police spokesman Micky Rosenfeld.

The source says agents now believe the suspect used an anonymizer to mask his phone number and IP addresses, and may have programmed calls in rapid succession.

Meanwhile, his public defender said the man “suffers from a brain tumor that may have had an effect on his cognitive functions.”

Galit Bash CBS News

“This is a young person that because of his very, very serious medical condition didn’t serve in the army, didn’t go to high school, didn’t go to elementary school,” said Galit Bash, the lawyer.

“Even though now there may be some relief, it’s not a time for institutions to ratchet back on their security protocols,” said Evan Bernstein with the Anti-Defamation League.

“It’s a time to maintain the diligence and not get complacent in any way,” he said