Earlier this week, 17-year-old Matin Azizi-Yarand was arrested for plotting a terrorist attack on a local mall near Dallas. This plot is the 103rd Islamist terror plot in the U.S. since 9/11.

Significantly, Azizi-Yarand was radicalized here in the U.S., making this an act of homegrown terrorism. Unfortunately, he’s far from the only person to be radicalized in the United States. His planned attack is the 90th plot or attack that was significantly or entirely homegrown.

Swearing allegiance to ISIS, Azizi-Yarand carefully planned the details of an attack with other individuals. What he didn’t realize was those other individuals were actually FBI undercover agents and informants.

Azizi-Yarand came into contact with an FBI source online in December and began to discuss either traveling to the Middle East or plotting an attack in the U.S. He made clear his Islamist terrorist sympathies, praising other “lone wolves” who engaged in terrorism. Azizi-Yarand also spent significant time reading terrorist propaganda and materials on how to carry out terrorist attacks and build bombs.

Once Azizi-Yarand decided to attack here at home, he thought about attacking a school but then decided on a local mall. Conversing with other undercover FBI sources, he planned the attack. He scouted the location to figure out the movement of security guards; coordinated the gear and the number of bullets needed, even giving the undercover agents over $1,400 to buy gear and weapons; prepared a speech he would give; and even secured training to ensure they were ready for the attack.

However, Azizi-Yarand was arrested before his 18th birthday when he planned to buy his weapons.

Azizi-Yarand’s homegrown radicalization indicates that even as ISIS crumbles as a military force on the battlefields of Syria and Iraq, its ideology and propaganda continue to resonate with others around the world.  It’s not enough to militarily defeat terrorist groups and safe havens. It’s clear groups like ISIS must also be ideologically defeated, their arguments and values addressed directly.

Another takeaway from this case is that it is the 44th time a plot was foiled with a sting operation in which law enforcement undercover officers played along with Azizi-Yarand to discover the full extent of his terrorist plans.

While intelligence from electronic sources is a critical tool to identifying terrorists, human intelligence is a powerful tool to reveal the depth of a terrorist’s activities and to use in court to convict them. Having a robust and proactive set of intelligence tools and resources is essential to stopping terrorists before they strike.

Given the homegrown nature of this and many other terrorist plots and attacks, Congress should consider greater investments in and improvements to U.S. intelligence tools to keep Americans safe.