Flowers and pictures of victims have been laid in front of the Reina nightclub on January 5, 2017 in Istanbul, four days after a gunman killed 39 people on New Year's night.  
Elite Turkish police arrested several people today during fresh raids over the nightclub attack that killed 39, as authorities tightened Turkey's borders to prevent the fugitive killer from escaping. / AFP / OZAN KOSE        (Photo credit should read OZAN KOSE/AFP/Getty Images)