Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: At first glance, the life of Seifeddine Rezgui appeared to be like that of any other young Tunisian man. An avid football fan, his family have described the 23-year-old as a young man who enjoyed all the trappings of Western society. A supporter of Real Madrid, Rezgui loved breakdancing and sitting in cafes chatting with friends. But beneath the veneer of normality, a radicalism was brewing which erupted on Friday with the massacre of 38 people on a Tunisian beach. Today more details of his character have emerged - including a video of a teenage Rezgui breakdancing - which offer a sharp contrast to a murderous state of mind.Terrorist Seifeddine Rezgui loved breakdancing and supported Real MadridBut his Facebook postings reveal he harboured strong support for ISISIn one post, 23-year-old said he wanted the 'people of the world to suffer'A video of the engineering student breakdancing also surfaced todayFilmed in 2010, a teenage Rezgui is seen wearing a cap, hoodie and jeans 
 Question:_ have since taken credit for the attack, releasing images of a smiling Rezgui next to two assault rifles.

ISIS