The St. Louis Park family had just started a two-month vacation with relatives in Morocco in 2015 when they noticed that their 18-year-old son was on his cellphone even more than usual.

He told them it was just a distraction while adjusting to the Casablanca area, a place he found more hectic than his suburban hometown.

But within days, Abdelhamid Al-Madioum had disappeared.

His parents now know that the young man had secretly booked a flight to Istanbul, on his way to Syria to join the Islamic State of Iraq and Syria (ISIS).

His case, laid out in newly unsealed court filings, is the first new disclosure of a young Minnesotan attempting the terrorism pilgrimage since the high-profile prosecution of nine Twin Cities men drew national attention last year.

And while that case seemed to close a chapter on one of the FBI's biggest terror recruitment probes, the new documents underscore what federal authorities have been quietly saying for months: Their investigation of terrorist recruiting in Minnesota is far from finished.

In addition to Al-Madioum's case, the Star Tribune has identified at least five other open investigations alleging ISIS support in Minnesota, with cases from 2015 to as recently as late last year.

Officials from the FBI and the U.S. attorney's office in Minneapolis would not comment on Al-Madioum's case. But search warrant affidavits reviewed by the Star Tribune outline an intricate plan by the young man, including months of careful preparation involving money transfers and border crossings.

Searching his bedroom in St. Louis Park, FBI agents found handwritten notes with a sketch of the symbol that adorns the ISIS flag, next to the word "allegiance" written in Arabic.

In another, the young man wrote: "If we leave the U.S. with no one stopping us, we have succeeded."

Secret plans

Al-Madioum, a naturalized U.S. citizen, was to spend two months with his family visiting relatives in Morocco in June 2015. His parents later told investigators that he skipped dinner on July 7 and said he wasn't feeling well, but still prayed and visited with family until going to bed about 3 a.m.

The next day, finding him gone, relatives scoured local hospitals and police stations, according to the FBI's search warrant application. Their home's front-door key was missing, as were Al-Madioum's cellphone and passport. His other possessions had been left behind.

Soon, Moroccan officials told the family that Al-Madioum had booked a flight to Turkey that left Casablanca hours after they last saw him. In many cases, according to an agent's sworn affidavit, aspiring ISIS militants try to cross into Syria by first traveling to Istanbul.

After several failed attempts to reach their son by text and social media, the family went to the U.S. Consulate to ask for the FBI's help, according to the search warrant. On Aug. 21, they returned home without him.

Meanwhile, the family allowed the FBI to search its home in St. Louis Park. Agents retrieved three laptops and two hard drives, along with pages of handwritten notes in Al-Madioum's bedroom.

The notes showed that Al-Madioum had created a "flow chart" of how he planned to route money through alternative bank accounts to make sure he had access to funds "should his travel plans become obstructed." He listed "Ali's account," PayPal, MoneyGram and "paying someone on the spot" among his options, according to the FBI's search warrant application.

He also wrote down questions like the maximum withdrawal limit for his check card and how to prove his identity over the phone. The FBI said Al-Madioum also appeared to write out a "rehearsed backstop story" should border officials question him as he tried to enter Turkey.

Al-Madioum's family has since moved out of St. Louis Park. A woman and man who answered the phone at a new Twin Cities-area address listed for the family declined to comment for this story.

The FBI's investigation into the case is still open, and a spokesman declined to comment on the case.

Eighth local identified

Al-Madioum's motivation remains a mystery, but he was far from alone. The year he vanished was a banner year for people traveling overseas to join ISIS or being stopped from doing so by authorities, according to Seamus Hughes, deputy director of the George Washington University Program on Extremism.

"It was also the height of ISIS messaging, so it's probably a fair assessment that [he] traveled because he perceived an obligation to join the so-called caliphate," Hughes said.

Authorities believed Al-Madioum was in touch with one or more ISIS recruiters via social media or e-mail, according to an agent's search warrant application. It is unclear what agents found on the electronic devices.

Hughes said he would be surprised if there was not an element of "peer-to-peer" recruitment, as with the young Somali-Minnesotans who plotted to go to Syria in 2014 and 2015. "If not, this is truly an outlier," he said.

Al-Madioum is now the eighth Minnesotan identified as being under suspicion of leaving his family behind to join ISIS.

The FBI has said that it has 1,000 counterterrorism investigations open, spanning all 50 states, and Minnesota has seen more than most. Three of the suspected Minnesota travelers have been charged and nine others convicted of trying to follow them.

Since 2015, the flow of Americans trying to join the terror group overseas has slowed to a trickle of just one or two per month. That may reflect a shift in recruitment messaging: As it has lost territory in Syria and Iraq, ISIS has been encouraging its followers to commit attacks in their home countries.

'Sign of life' call

Al-Madioum, who would now be 20, studied engineering at Normandale Community College from June 2014 to May 2015. According to the search warrant, he also worked part-time for the college's IT department. But little else is known publicly about him. A Facebook page with most of its content made private lists an Al-Madioum from St. Louis Park as having also attended Hopkins High School.

The only post that shows up publicly on this page notes that in April 2011 he "liked" an article on "BroBible" called "The Stoner Bucket List: 20 things to do for 4/20."

Four days after Al-Madioum's family returned from vacation, in August 2015, Al-Madioum called them twice.

FBI agents speaking with family on the following day learned that at first he hesitated to tell them where he was, but "eventually claimed to be working in a hospital in Mosul, Iraq," which had been under ISIS control for more than a year at that point.

The FBI said that phone calls, which came 48 days after Al-Madioum disappeared in Morocco, fit a pattern: New ISIS recruits are allowed to place a "sign of life" call back home after about 30 to 45 days of "basic training."

"During these calls, ISIL recruits will misinform loved ones about their locations and their activities so as not to cause distress to loved ones," a member of the FBI's joint terrorism task force, using another common acronym for the terror group, wrote in an October 2015 search warrant application.

When asked by phone to discuss the family's last contact with Al-Madioum, a relative replied, "I'd rather not, sir."

Stephen Montemayor • 612-673-1755

Twitter: @smontemayor