Welt.de here says he had Breivik’s face as his profile picture in WhatsApp messenger program
http://www.welt.de/politik/deutschland/article157240657/Taeter-in-Muenchen-befasste-sich-intensiv-mit-Amoklaeufen.html
... the link goes on to Bild, but it is behind paywall.
Thanks.I will check later.