Indonesian Search And Rescue (SAR) team prepare a sonar equipment during a searching operation for the sunken boat at the Lake Toba, North Sumatra, Indonesia, on June 22, 2018. Indonesian authorities here on Friday used sonar technology to find victims of the sunken boat in Lake Toba, after the vessel capsized leaving at least four people dead and over 192 others missing. (Xinhua/Albert Damanik)