The extremist militia Islamic State (IS) has released a video purportedly showing the suspect responsible for the fatal knife attack in the western Germany city of Solingen. In the approximately one-minute video, a masked young man can be seen holding a long knife towards the camera. He pledges allegiance to the Islamic State leader in Arabic, referring to him with the honorary title “Emir.” On Saturday, Islamic State claimed responsibility the attack in which three people died and eight others were severely injured. The authenticity of the video and whether the man shown in it is indeed the s…