The men were between 20 and 23 year old, and had filmed their actions with the cell phone, police said on Thursday. Also during the search of their apartments proof had been found. The fire had been placed late on Tuesday evening in a two-storey office building of the slaughterhouse. People did not come to harm. It took the fire brigade two and a half hours to extinguish the fire. On the site in the district of Gröpelingen it had burned, according to the fire Department several times already.