if others are already radicalised, they'll simply continue to radicalise others. that's why this preventive action is very important. >> the chaplain speaks to the prisoners one-on-one and uses prayers to try and prevent radicalisation. >> we have muslims who themselves come from germany, who say that everyone in the west is an infidel, even though they are themselves western. so they're denying themselves. we need to explain these contradictions to them. >> this prisoner is in investigative custody for violent crime. he's already been approached by jihadists. young muslims, he says, are especially vulnerable. >> they hear things like you go there, you get a gun, you can shoot people listen to you, you're important, you have a position of power in a place you couldn't have been before. of course that attracts young people. >> the so-called islamic state continues to attract new recruits in germany as well as elsewhere. >> the number of people leaving is no longer as high as it was in the summer of 2014, when the so-called caliphate was declared. the boom has dimin