French police arrested a suspect in last month’s deadly shooting at the Jewish Museum in Brussels, Belgium – and the suspect has ties to the Islamic State of Iraq and Syria (ISIS), the jihadist group so violent it is was criticized and cut loose from the mothership of terrorism, al Qaeda.

The bus from Brussels carrying 29-year old Mehdi Nemmouche had just arrived in Marseilles on Friday when the 29-year old French citizen stepped off and into a routine customs check.  Authorities say they found that Nemmouche was carrying an AK-47 assault weapon and a revolver matching the description of the weapons used in the museum attack on 24 May.

Nemmouche was also packing a hat and shirt matching those worn by the shooter captured by the Jewish Museum of Brussels’ security camera before, during, and after the shooting.  Most damning was the video he was carrying in which he took credit for the attack, in which two Israeli tourists and a French museum docent were killed and a Belgian man was injured.

But Nemmouche was on the authorities’ radar since 2001, with a series of convictions ranging from driving without a license to a violent robbery.  He was pegged as a potential jihadist upon his most recent release from in 2012, but that didn’t stop him from traveling to Syria to fight with ISIS, whose reckless tactics that frequently result in dead children got it kicked out of al Qaeda.

As many as 3,000 Europeans are believed to be fighting with, or have fought alongside with, Islamist forces opposed to Syrian President Bashar al-Assad.  The Brussels Museum shooting is believed to be Europe’s first terrorist attack carried out by a ‘veteran’ of that three-year-old civil war.