The Jewish Israeli-American arrested this week on suspicion of making a host of bomb threats on Jewish institutions worldwide has been making such cyberattacks for two years, but only recently was his capture given high priority, according to police sources.

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The sources attributed the turnabout to pressure from United States President Donald Trump. A few weeks ago, after Trump announced that the FBI would do everything in its power to catch the perpetrator, the agency sent 12 investigators from its cybercrime unit to Israel to assist the Israeli investigation.

The 19-year-old was arrested in the Israeli city of Ashkelon on Thursday by cybercrimes unit of the Israel Police, seizing computers and other items investigators say helped the suspect evade detection.

The police have not yet heard the teen’s story, as he is maintaining his right to remain silent. Police sources said he has so far refused to talk about anything except the fact that he is sick. Police also haven’t yet succeeded in breaking into his computers, but expect to accomplish this in the next few days.

What they have managed to determine, the sources said, is the teen’s modus operandi. After calling in one of his bomb threats he would watch the media to see what effect the threat had. If he saw that a threat was getting media attention, he would make more threats in the same location.

Altogether, the teen has made hundreds of threats that the public never heard about, police said. When they got no media attention, he stopped making threats in those places. In contrast, the bomb threats to Jewish institutions in the U.S. in recent months received especially prominent coverage, not just in America but worldwide, so he began focusing his threats on those institutions.

It’s not clear whether the teen had any accomplices. Police said he isn’t enrolled in or active on any social media network under his own name, though it is possible he was using an alias. The teen’s father has also been arrested, on suspicion that he knew what his son was doing but kept quiet. The father is a computer expert, who would have known very well what the specialized equipment in his son’s room was for, police said.

As yet, there has been no U.S. extradition request, but police said that if one is received, they believe Israel will accede. They also speculated that commercial companies hurt by the teen’s threats might file civil lawsuits against him.

Police plan to question the teen’s mother in the next few days, but are waiting for her to obtain relevant medical documentation so they can examine the family’s claim that his health problems mean he cannot be held responsible for his actions.

The teen’s public defender, who visited him in jail on Friday and has spoken with him several times over the last few days, said she is increasingly convinced that his health problems have been influencing his behavior. “He told me several things that need to be checked out,” said the attorney, Galit Bash. “I’ve also been in contact with his mother, and she gave me critical information – very, very essential. Apparently there’s an opinion by neurologists who say this affects his behavior.”

During the bail hearing, she said the teen has an inoperable growth in his head. Bash is expecting to get the medical documentation on Monday. Bash said the teen was born in Israel, but left the country with his family at a young age and has since returned several times. “He left school in first grade; his parents begged for someone to operate on him,” she said. Yet despite not being in school, he was also never in the care of the welfare authorities, Bash said.