Europe reacted in shock to the third attack on the continent in just over a week, after 18-year-old David Ali Sonboly went on a shooting spree at a shopping centre on Friday in what appears to have been a premeditated attack, before turning the gun on himself.
Officials said Sonboly, a German-Iranian student, had a history of mental illness.
Interior Minister Thomas de Maiziere said the teenager had likely hacked a girl’s Facebook account and used it to lure victims to the McDonald’s outlet where he began his rampage.
“There is absolutely no link to the Islamic State,” Munich police chief Hubertus Andrae said, with prosecutors describing the assault as a “classic act by a deranged person”.
Investigators see an “obvious link” between Friday’s killings and Breivik’s massacre of 77 people in Norway exactly five years earlier, Andrae added.
Chancellor Angela Merkel said Munich had suffered a “night of horror”.
Most of the victims in Friday’s attack were young people, with three aged just 14, police said.
Munich prosecutor Thomas Steinkraus-Koch said Sonboly had suffered depression, but voiced caution over reports he may have undergone psychiatric treatment.
The teenager had 300 rounds of ammunition in a rucksack when he targeted the busy Olympia shopping mall, just minutes away from the flat he shared with his family, according to authorities.
Police are investigating how he managed to obtain his weapon, a 9mm Glock pistol with a defaced serial number.
Germany’s bestselling Bild newspaper pointed out that a Glock pistol was also among the firearms used by Breivik.