this is halla barakat reporting from istanbul. >> halla and ouruba settled in istanbul, turkey, wherehe became a vocal member of the syrian opposition. >> we'll stay here, we'll stay in camps. >> which was working against the regime in damascus working against president bashar al assad. >> it's a harmful regime that doesn't care about our people. >> they felt the assad regime is brutal, and there's no justice in syria as long as he and his family have been in charge. halla was last heard from, from her colleague. when she didn't show up to work, her colleague called her friends. >> halla's friend went to check on her, and there was no answer when she knocked on the door to the apartment. >> so the police came, they had a locksmith open the door. and that's when they saw the bodies. >> it was a shocking video. it just showed an absolutely grisly crime scene. >> the bodies had been covered in blankets, detergent had been sprinkled on the blood on the floor. >> that seemed to be a way to conceal their odor from decomposition, which would give the killer or killers time to get away, days

as soon as murders might very late this must be a warning and a mandate at one side and the case of halla and. we know who perpetrated these crimes of innocent a few may have listened but we need to know so much more than not need to get to the bottom of the moat we've just got behind this you must investigate the background of crimes like this we must unearth the networks in order to recognize these risks and to prevent these crimes wherever we can and this is 1st and foremost the job of the state and its security organs but it's important for all of us these perpetrators do not come out of nowhere. and shows up it's not just when they throw bones or light fires off fire shots. that we 1st hear of their thoughts the terrorist hull is presumed to have acted alone but he is certainly not a longer this hatred and this is a very of the lone wolf as we know today has too often in the past distracted us from a core. terrorists like this have an environment in which they even become more radicalized they are embedded in networks in virtual ones and real honest they have supporters virtual ones

this special edition of "nightline," justice for halla, will be right back.