The Tunisian man and failed asylum-seeker who used a semi-truck to plow into crowds of people at a Christmas market in Germany last December received the assignment from Islamic State leadership, according to German magazine Der Spiegel.

The terrorist, Anis Amri, had been suspected by German authorities of being linked to the Islamic State, and ISIS had claimed responsibility for the attack, but security officials could not verify if Amri had received direct orders, or had merely been inspired by ISIS.

Confirmation of a direct ISIS link in the operation was confirmed by German authorities through intelligence provided by the United Arab Emirates on January 8. The operation was reportedly planned and executed through the Islamic State’s “external operations” cell. The same cell is known to German authorities for infiltrating ISIS operatives into Europe disguised as refugees.

Amri’s attack in Berlin was the second major terrorist attack using commercial trucks as a weapon to crush bystanders in crowded areas. After hijacking the truck, Amri killed the driver, leaving his body in the cab of the vehicle throughout his attack. After plowing through a crowded Christmas market, Amri had killed 12 people and injured 56.

After the truck came to a stop, Amri fled the scene, only to be shot and killed by Italian police in Milan four days later.

The most infamous use of trucks as a terror weapon occurred in Nice, France last summer. There, a native Tunisian living in France killed 86 people and injured over 400 by driving into a crowd celebrating the French holiday Bastille Day. This was not the first use of trucks as a weapon in France. Twice in 2014, two different men with mental disorders used vehicles to strike people in crowded areas. However, no deaths occurred as a result of their actions.

Law enforcement authorities in the U.S. and Europe have repeatedly warned against the effects of “lone wolf” attacks, or those individuals inspired to conduct independent terror attacks without direct connections or guidance from an established terrorist group. None of the jihadist attacks that have occurred inside the United States since the rise of the Islamic State have been confirmed as directly planned and executed by ISIS operatives. Among the dozens of jihadist attacks that have occurred in Europe, only a few are believed to have been executed directly by ISIS: the Paris attacks in November 2015, the Brussels airport and subway suicide bombings in March 2016, and the Ataturk airport suicide bombings in June 2016.

Before the attack, Amri released a video pledging allegiance to ISIS and its leader, Abu Bakr al-Baghdadi.