A 32-year-old man on Monday confessed to selling the gun and bullets used by a teenager to kill nine people in a shooting spree at a Munich mall last year.

The suspect, Philip K., told the court at the start of his trial in the southern German city that he "would have never sold him the weapon" if he had known that the gunman was planning "such a horrible act".

In a statement read out by his lawyer, he also expressed his "sincere condolences" to the families of the victims.

The 18-year-old attacker, David Ali Sonboly, killed himself after his murderous rampage at Munich's Olympia shopping centre in July 2016, using the gun he had bought through the darknet, a hidden part of the internet.

Prosecutors argue that the killing spree would not have been possible had Philip K. not provided the Glock 17 and hundreds of rounds of ammunition, at a price of around 4,500 euros ($5,300).

He was arrested in August 2016 and charged with negligent homicide, illegal arms trafficking and other weapons violations.

As his trial began on Monday, the suspect admitted to the weapons charges and said he used the darknet to make contact with buyers before meeting them in person to make the transaction.

He had been dealing arms through the darknet since 2014 under the username "rico", the Munich court heard. One of his customers was a 17-year-old student.

The judges also heard that investigators found a video of Philip K. giving the straight-armed Hitler salute on his mobile phone, along with pictures of the truck attack in the French city of Nice that killed 86 people a week before the shooting happened.

Investigators searching his home also found Nazi symbols on his computer hard drives.

Police believe Sonboly, who suffered from psychological problems and was bullied at school, had planned his attack for over a year.

They have also said that the gunman was obsessed with far-right extremist Anders Behring Breivik, whose massacre of 77 people in Norway came exactly five years before his own shooting rampage.

Philip K.'s trial is set to run until September 19. If convicted, he faces several years in jail.

Source: AFP