Investigators are trying to decide whether or not to charge Ayoub El Khazzani, the 25-year-old man who stepped on-board a train carrying an assault rifle. By French law, investigators have until Tuesday night to interrogate the suspect, according to Yahoo! News.

Khazzani opened fire on the train, but was overpowered by a couple of U.S. Marines and several others who were on-board. No one was killed. Investigators are still trying to fill in some of the blanks in the suspect's past. The men who subdued the shooter were awarded France's highest honor - the Legion of Honor - on Monday. 

A French prosecutor says that the suspect watched a video on his phone just minutes before he stepped onto the train. The jihadi video suggests terrorism, but Khazzani denies having any ties to any terrorist organizations. He says he was planning to rob the train, not shoot it up, according to SFGate.

Surveillance suggests that he has recently traveled to Turkey, but the suspect denies going there. Police say they have uncovered multiple pieces of evidence that link the suspect to participation in a terrorist conspiracy. Turkish authorities are assisting in the investigation, according to The Wall Street Journal. The suspect must be charged with a crime, or he cannot be held for questioning beyond Tuesday night.