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Prosecutor: Train suspect watched jihadi video minutes before attack

French police stand over a man who is apprehended on the platform at the Arras train station after shots were fired on the Amsterdam to Paris Thalys high-speed train in Arras, France, Aug. 21, 2015.

Christina Cathleen Coons/Handout via Reuters

Last Updated Aug 25, 2015 12:18 PM EDT

PARIS -- French authorities formally opened a terrorism investigation on Tuesday after a thwarted attack on a high-speed train last week, saying the suspected attacker had watched a radical Islamic video onboard minutes before the violence.

Prosecutor Francois Molins said Tuesday the decision to open an investigation was based on the actions by 26-year-old Moroccan suspect Ayoub El-Khazzani on the train Friday night and information from other European authorities about his travels and apparent links to radical Islam.

Molins said El-Khazzani notably watched the online video on his phone minutes before he walked through the Amsterdam-to-Paris train carrying an assault rifle and other weapons.

Authorities say that they found the suspect's phone in a bag left in the train. El-Khazzani boarded the train on Friday at a Brussels station.

The gunman was tackled and tied up by a group of three American friends and a British businessman. Another man who tried to stop him - a French-American named Mark Moogalian - remained hospitalized with a gunshot wound.

Now that the formal investigation is opened, investigating magistrates are expected to file numerous charges against El-Khazzani, including an attempted terrorism-related attack.

El-Khazzani was found to have an AKM assault rifle with 270 rounds of ammunition, a 9mm handgun, a box-cutter and a bottle of gasoline, the prosecutor said.

El-Khazzani had travelled through several European countries and had been repeatedly incarcerated in Spain, Molins said.

A senior U.S. official tells CBS News that El-Khazzani does not have any apparent links to anyone in the U.S. that investigators have found so far. This official tells CBS News that while El-Khazzani attempted to get to Syria, it is unclear whether he was successful.

In questioning, El-Khazzani initially said he had found a bag of weapons the night before in a Brussels park and planned to use them to rob passengers, according to Molins. But his explanation grew less and less lucid, the prosecutor said, and the suspect eventually stopped speaking to investigators at all.

Meanwhile, details of another hero aboard the train emerged. Mark Moogalian and his wife were seated facing each other on the high-speed train when he suddenly told her, "Get out, this is serious." Then, Isabelle Risacher Moogalian said, she ducked behind some seats as he lunged to grab the assault rifle from the gunman's hands.

"When my husband collapsed, I saw across the seats. He looked at me and he said 'I'm hit, I'm hit.' He thought it was over and he was going to die," she told Europe-1 radio. The bullet struck him in the back and exited through the neck.

The American teacher and artist who has lived in France for more than two decades has emerged as another hero in the high-speed train attack thwarted by a group of quick-thinking men. According to French President Francois Hollande, a Frenchman was the first to encounter the gunman as he left the toilet, alerting others in the area. That person, Hollande said, wished to remain anonymous.

Moogalian remained hospitalized Tuesday in the northern city of Lille, and his sister in Virginia said his role in trying to stop what French authorities are calling a terror attack was in character.

Stone, Alek Skarlatos, Anthony Sadler and a British businessman who joined the fray to help subdue the attacker were awarded Monday the Legion of Honor -- France's highest honor -- by President Francois Hollande.

CBS News correspondent Charlie D'Agata reports that Mooglian and an as-yet-unnamed French passenger who also helped out will also receive awards for their bravery at a later date.

An official at Landstuhl told CBS News Tuesday morning that Stone would be treated at the base for the laceration to his thumb, a non-critical injury to his eye and other minor cuts and scratches.