There were three claims of responsibility: one left at the scene claiming an Islamist motive, one posted on the internet claiming an 'anti-fascist' motive (which was deemed to be fake), and one later sent to a newspaper claiming a far-right motive.
有三份宣称负责的宣言，遗留在现场的一份声称伊斯兰主义动机，在网上发布的一份声称“反法西斯主义”动机（被认为是假的），后来被送至一家报社的一份声称极右动机。