The teenage gunman who killed nine people in Munich on Friday had been planning his attack for a year, German authorities say.
David Ali Sonboly, 18, who killed himself after the attack, had a Glock pistol that police believes he may have bought on the so-called dark net.
Meanwhile police in Munich have announced the arrest of a 16-year-old Aghan friend of the attacker.
A statement on Munich police's Facebook page says: "There is a suspicion that the 16-year-old is a possible tacit accomplice to the attack."
Facebook post reporting the arrest of a 16-year-old Afghan boy in connection with Friday's shooting
The statement goes on to say that the youth reported to police immediately after the shooting on Friday, and was interviewed as somebody with a connection to the attacker.
But in the course of the interviews, they discovered discrepancies in his statements.
They say they are now investigating him on suspicion of failing to report a planned crime.
The investigations will have to show to what extent he was responsible for a Facebook post inviting people to meet at a cinema complex near the main railway station in Munich.
The attacker himself had put up a Facebook post before his attack, inviting people to come to the fast food restaurant where the shooting began.
'Not specifically targeted'
Seven of the dead in Friday's shooting at the Olympia shopping centre were were teenagers - two Turks, two Germans, a Hungarian, a Greek and a Kosovan.
A further 35 people were injured, but only four of them have bullet wounds - many were hurt while fleeing the scene.
The state government officials told a news conference that the victims of the attack had not been specifically targeted and were not classmates of the gunman.
Also they did not include three youths allegedly involved in bullying Sonboly when he was at school.
Source: Facebook
