After 19-year-old Akhror Saidakhmetov was arrested yesterday and charged with plotting to fight for the Islamic State, among other things, reporters and television crews showed up at his apartment in Brooklyn. There, a woman believed to be his mother, upon being told of her son’s arrest, began wailing.

“No, it can’t be,” she said. “It’s not true 

But it was true. And this was what she had feared and done her best to prevent, according to papers filed by federal prosecutors in the case. An ethnic Uzbek immigrant from Kazakhstan, she worried about other older Uzbeks in New York with whom her son was associating, like Abdurasul Hasanovich Juraboev, who was also arrested. She worried he might be vulnerable to the call of the jihadists. She confiscated her son’s passport, refusing on several occasions to return it to him. To get it back, he made up stories — about how he was really going to visit family in Uzbekistan — but she was not fooled. She still refused.

She did her best. And her efforts, outlined sketchily in the FBI affadavit in support of the arrests, illustrate something experts on foreign fighters have often said: preventing young people from being lured to fight for the Islamic State doesn’t depend on denunciations of its barbarity or counterpropaganda from the U.S. government. It’s the families of those young Muslims who count.

“The best line of defense in this whole issue is parents, family,” Imam Mohamed Magid of the All Dulles Area Muslim Society told ABC News earlier this week. “Complete awareness about your children, for instance, what they’re doing, who they are, friends they have in the virtual community, that’s very important.”

“ISIS is very savvy in the Internet,” Magid said, using another name for the Islamic State. “They see the traffic, who’s coming to watch and so forth and during that time that’s where they catch the young person when he shows curiosity.”

And young Saidakhmetov allegedly did show more than curiosity. He was caught up in the fervor, the affadavit suggests. When Islamic State videos last summer showed mass executions of Iraqi soldiers after extremist fighters took Mosul, millions turned away in horror. Not so Saidakhmetov. “’Allohu Akbar,’” he posted  on a jihadi Web site, according to the documents, and described his feelings as “very happy” at the news, his “eyes joyful” at “so much victory.” He watched videos of Islamic State training camps in Syria and expressed his urge to “go there” and “become a Mujahid on the path of Allah.”

What he didn’t know was that the FBI was monitoring him. With the help of a confidential informant pretending to facilitate their plans to travel to Syria, authorities knew of his conversations with Juraboev, 24, and another man, Abror Habibov, both of whom were also arrested yesterday and charged with conspiring to provide “material support and resources” to a foreign terrorist organization.

Habibov, 30, was clearly the most established of the three, operating a string of kiosks selling kitchenware and repairing mobile phones in Florida, Georgia, Pennsylvania and Virginia. But Juraboev, also known as “Abdulloh Ibn Hasan,” according to the documents, purported to be able to facilitate contact with fighters in Syria. Saidakhmetov, who had worked for Habibov, and Juraboev both occupied an apartment in Brooklyn paid for by Saidakhmetov’s mother.

A glimpse of how the older men regarded the younger is offered by an alleged exchange, reported in the documents, in which Saidakhmetov, using another acronym for the Islamic State, “expressed interest in joining the United States military so that he could pass information about the military to ISIL to help in their attacks.” Juraboev “expressed skepticism that Saidakhmetov could stay calm and avoid trouble in the military.” In response, Saidakhmetov allegedly said that “he could always open fire on American soldiers and kill as many of them as possible.” Later he allegedly boasted that if he was unable to get his travel documents for Syria, “I will just go and buy a machine gun, AK-47, go out and shoot all police. … It is legal in America to carry a gun.”

The mother apparently disapproved of the association. In December, according to the documents, she visited the apartment and asked how long Juraboev would continue to live there. Juraboev said he would be gone by the end of March. Still curious, the mother asked “where he was going,” the documents said. Lying, Juraboev said he would be heading to their native land, Uzbekistan.

As soon as she left, the three men — Saidakhmetov, Juraboev and the confidential informant — resumed planning their itinerary to Syria.

The big obstacle for Saidakhmetov, apart from being cash-strapped, was that his mother had confiscated his passport. Saidakhmetov allegedly complained to the others that “he wanted to travel to Syria to wage jihad, but that his mother had feared that he would do so and took his passport so that he could not travel. Saidakhmetov said he would try go get his passport back by telling his mother that he was traveling to Uzbekistan to visit relatives.”

Saidkhmetov appeared torn between loyalty to his mother and his desire to fight. At one point, according to the documents, as he inquired about obtaining money to fly to Turkey he also felt compelled to seek extra cash so that he could “repay his debt to his mother” before he left.

Habibov didn’t like that idea at all. He was “concerned” that Saidkhmetov’s mother would “raise an alarm,” and that “the authorities could then track” them down and “prevent them from going to wage jihad.”

According to the documents, Saidkhmetov had one final conversation with his mother just before his arrest. On or about Feb. 19, he called her once more to ask for his passport.

She asked where he wanted to go.

He allegedly responded that “if a person has a chance to join Islamic State and does not go there, on judgment day he will be asked why, and that it is a sin to live in the land of infidels.”

His mother “hung up the phone.”

Saidakhmetov was arrested at John F. Kennedy Airport, where authorities allege he was attempting to board a flight to Istanbul, with plans to head to Syria. Juraboev had a ticket to travel to Istanbul next month and was arrested in Brooklyn, federal prosecutors said. The two were held without bail after a court appearance. Habibov is accused of helping fund Saidakhmetov’s efforts. He was ordered held without bail in Florida.

Each faces a prison term of up to 15 years if convicted.