A series of encrypted phone calls ? secretly recorded by a confidential FBI source ? tipped off federal agents that a group was allegedly planning to carry out a terrorist attack in Michigan on behalf of ISIS, according to a criminal complaint unsealed Monday.

Mohmed Ali, 20, and Majed Mahmoud, 20, face charges of ?Receiving and transferring, and attempting and conspiring to transfer, firearms and ammunition knowing and having reasonable cause to believe that the firearms and ammunition would be used to commit a Federal crime of terrorism,? according to the criminal complaint.

Federal officials have yet to charge a third person ? a juvenile described throughout the complaint as Person 1 ? in connection with the alleged plot.

But the complaint details how agents doggedly surveilled the alleged co-conspirators for two months as they visited multiple gun ranges and held late-night meetings in local parks during what authorities allege was preparation for a possible terrorist attack.

Then, based on what they believed to be references to a possible attack on Halloween, agents swooped in to seize the weapons and take the men into custody in the predawn hours of October 31.

Here?s what we know about how the investigation unfolded:

A cryptic reference to Paris prompts suspicion

According to an FBI affidavit supporting the criminal complaint, the agency began surveilling a man, described as ?co-conspirator 1,? in 2024 as he traveled in the US and overseas.

In June, agents allegedly tracked the man?s phone to Dearborn, Michigan, and physical surveillance led them to Ali?s home there, where he stayed for two nights.

The following month, according to the FBI, the man joined a group call from overseas with five others ? including an FBI confidential source, who recorded the meeting. Person 1, Mahmoud and Ali do not appear to have been part of this call.

During the call, the group allegedly discussed ?traveling together to Syria to join ISIS? and co-conspirator 1 said they were ?gonna die there ? unless,? he told the group, ?the Amir sends you to Paris for a 2015.?

A review of co-conspirator 1?s cellphone allegedly revealed he had ?Person 1?s phone number saved in his phone under ?Athari? and ALI?s phone number saved in his phone as ?Bukhari.??

According to the complaint, one of the participants on the call also stated, ?Athari and Bukhari said they were going to stay back and do the ?same thing as France.??

?Knowing Athari, it?s (the attack) probably going to be at like a club, a disco,? co-conspirator 1 said, according to the complaint.

The reference to Paris stood out to FBI counterterrorism experts. They concluded it was a thinly veiled nod to the coordinated ISIS-linked terrorist attacks that unfolded across Paris in November 2015. More than 130 people were killed in the attacks and scores more were wounded.

After studying the call, the FBI concluded an attack could be imminent and began keeping close tabs on Ali and Mahmoud.

Talk turned to action with purchase of firearms, complaint alleges

According to the complaint, in the months following the June meeting with ?co-conspirator 1,? Ali allegedly purchased a Beretta A300 Ultimata Black Shotgun, a ?Sabre? Forged 16? rifle, as well as a holographic sight ?built for close-quarter engagements with fast moving targets.?

Mahmoud also allegedly purchased a rifle and two boxes of ammunition with more than 800 rounds in each box. In October, he allegedly purchased a red dot sight, which provides ?the shooter a single point of focus during the aiming process,? according to the complaint.

Then, in September and October, Ali, Mahmoud and Person 1 began practicing at local shooting ranges, under the watchful eye of FBI agents, the complaint states.

Security footage obtained by the FBI shows all three men visiting local gun ranges over the course of several weeks.

On multiple occasions, undercover FBI agents entered the range and surveilled the men from nearby as they practiced firing weapons. Although the agents did not identify themselves, according to the complaint they observed the men practicing with guns and ammunition like those they had previously purchased.

FBI tailed trio as they allegedly scouted locations

Although Ali, Mahmoud and Person 1 are all under 21, the complaint noted in September they began traveling to a popular area in Ferndale, Michigan, known for its bars and clubs.

?Many of the clubs and bars in this area intentionally attract members of the LGBTQ+ community,? the complaint states.

The following month, FBI agents ?observed three individuals appearing to match the physical description? of Person 1, Ali, and Mahmoud meeting at a local park in Dearborn, Michigan, around 9 p.m. They met up again the following week at another park.

Since the men all live with their families, the FBI concluded the late-night meetups at the park ?reflect their efforts to meet to plan an attack without being detected.?

References to ?pumpkin? trigger arrest on Halloween

In September and October, the FBI received court-approved authorization to surveil communications between Person 1, Ali and Mahmoud.

In calls and messages, they found multiple mentions of ?pumpkin,? which agents concluded was a reference to ?Halloween as the potential day for the attack they were plotting, an attack that they understood could result in their deaths and martyrdom.?

?So ya, I talked to my brothers. We are going to do pumpkin,? Person 1 allegedly told Ali on October 24, according to the complaint.

The FBI later notes in the complaint references to ?brothers? likely mean ?other ISIS supporters.?

As the Halloween weekend loomed, a judge authorized the execution of search warrants on Ali and Mahmoud?s homes.

In the predawn hours of October 31, FBI agents descended on the Detroit suburb where the men lived and detonated smoke bombs before storming into their homes.

Both Ali and Mahmoud were arrested.

FBI Director Kash Patel later tweeted about the foiled terrorist plot but offered little additional detail. As a result, some Dearborn residents speculated whether the arrests were justified, or perhaps a way to profile the city?s large Arab population, which has long been targeted for Islamophobic attacks.

But on Monday, Attorney General Pam Bondi boasted on X the unsealed criminal complaint revealed ?a major ISIS-linked terror plot.?

?Our American heroes prevented a terror attack,? Bondi wrote.

Court process begins with hearing

Both Mahmoud and Ali were shackled as they were escorted into court Monday, according to CNN reporters who attended the hearing. Both men acknowledged they had read the complaint against them and understood the charges.

Attorneys for both of the men briefly spoke to reporters after the hearing, but declined to comment.

Co-conspirator 1 has not been charged.

If convicted, Ali and Mahmoud could face up to 15 years in federal prison and a $250,000 fine, a spokesperson for the US Attorney?s Office for the Eastern District of Michigan said. (CNN)

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