Maybe he wasn’t literally next door, but this ISIS operative – his target, Washington, DC – lived just streets away from my family.

My wife and kids shopped in the same grocery stores, the same Targets, the same Walmarts – as he planned his attack.

Thankfully, the FBI just arrested him this morning.

According to the U.S. Attorney’s office, this radical jihadist was plotting to assist ISIS (the Islamic State) in any way he could.

Haris Qamar, age 25, expressed his “excitement” about ISIS because of its “extreme violence.”  What he told FBI informants is chilling to the bone:

Qamar said he loved the bodies, blood and beheadings, and he recalled watching a video of a Kurdish individual being slaughtered, and liked the cracking sound made when the individual’s spinal cord was torn.

He “operated over 60 variations of the Twitter handle ‘newerajihadi’, which Qamar used to express his support of ISIL and share videos and photos of extreme violence, including beheadings and mass shootings.”

It’s not just sick.  It’s demonically evil, and he was right down the street.  As the U.S. Attorney’s office describes:

On several occasions Qamar allegedly said he could slaughter someone and described how he would do it.  Qamar also stated that he admired lone wolf attackers because they love Islam so much that they are willing to die as martyrs for Islam and in the same conversation, Qamar and CW [the FBI informant] allegedly discussed suicide bombings. CW said that he did not believe in suicide bombings, but Qamar allegedly responded “I believe in it 100 percent.”

Qamar apparently tried to “join” ISIS as early as 2014, but his parents threatened to turn him in to law enforcement and confiscated his passport.  Qamar called his father “a traitor to Islam,” and told the FBI informant that if he was able to get his passport back he would immediately leave to join ISIS, saying, “I’m done, I leave.”

Even worse, the U.S. Attorney’s office alleges:

On Sept. 11, 2015, terrorists connected with ISIL posted a “kill list” to the internet containing the names and addresses of U.S. military members.  A few days later, Qamar allegedly told CW that the residences of several service members who appeared on the “kill list” were near Qamar’s own home, and that Qamar had observed undercover police cars near those residences.  According to the affidavit, on Sept. 16, 2015, Qamar tweeted his prayer that Allah “give strength to the mujahideen to slaughter every single US military officer.”

And more:

According to the affidavit in support of the criminal complaint, on May 26, Qamar and FBI confidential witness (CW) discussed ISIL’s need of photos of possible targets in and around Washington, D.C., for use in a video that ISIL was purportedly making to encourage lone wolf attacks in the Washington, D.C., area.  Qamar allegedly offered CW ideas of where to take these photographs, including the Pentagon and numerous landmarks in Arlington and Washington, D.C., which could be targeted for terrorist attacks.  On June 3, a conversation was audio and video recorded when CW picked up Qamar in a vehicle and they drove to area landmarks on the list Qamar had developed.  Qamar allegedly said “bye bye DC, stupid [***] kufar, kill’em all”.  Qamar and CW met again on June 10 and drove to a location in Arlington to take additional photos for the ISIL video.

That was less than a month ago.  It sends shivers up my spine to think what could have happened if the FBI hadn’t infiltrated this jihadist plot.

As we have highlighted before, the infiltration, through human intelligence of jihadist operatives is one of the biggest keys to defeating the threat of ISIS and its jihadist allies.  As we explained in the ACLJ’s five-point plan to defeat ISIS:

Consistent with this emphasis on improved intelligence, and despite opposition from civil libertarians across the partisan spectrum, the U.S. needs to continue to ramp up its undercover sting operations designed to smoke out ISIS activists.

Since social media has given extremists a cloak of anonymity, these undercover stings — online and in person — are vital to gathering evidence and deterring possible attacks in the United States.

While the FBI has increased its use of this valuable tool, the government should make sure that this tool is widely available in order to thwart attacks by individuals like Omar Mateen despite opposition from defense lawyers, Muslim leaders, and other advocates.

Today, thankfully, this exact law enforcement and counterintelligence tool was utilized to save lives.

One thing is for certain.  No matter what President Obama says or how much he wants to downplay the threat, ISIS is here.  It is growing support.  Its adherents are following its public directives.  And they are motivated by a jihadist adherence to radical Islam.

And they might be just down the street from you.

Matthew Clark is Senior Counsel for Digital Advocacy with the ACLJ and Contributing Editor at RedState. Follow Matthew Clark: @_MatthewClark.