The German government has called for EU-wide gun controls in the wake of the Munich shootings, as it emerged the teenage attacker bought a gun on the “dark web”.

One of the mysteries of the attack has been how Ali Sonboly managed to get hold of a Glock handgun and the 300 rounds of ammunition police found in his backpack.

Police now believe he bought the gun on the so-called “dark web”, an area of the internet not accessible without special software, used by criminals and paedophile networks, according to Süddeustche Zeitung newspaper.

The gun was a deactivated weapon certified for use as a theatrical prop which had been reactivated before the attack.

The handgun’s most recent documentation was from Slovakia in 2014, raising concerns over the ease with which guns can be bought and sold around the border-free Schengen Area.