premise: "The raid was perpetrated by the rebels from the National Redemption Front, who are committed to a military escalation," interim governor Mohammed Yusef al-Tulib was quoted as saying by the state-run SUNA news agency.
  He also provided a lower casualty toll of 15 dead and 14 wounded, saying the attack targeted a bus carrying 34 civilians near the border with Chad.
  Eight AU observers, who were sent to investigate the incident, and their helicopter crew were held for 24 hours by an angry crowd near Sirba, the African body said.
  Local residents insisted the AU team take pictures of the bodies and prevented them from flying out. The observers were eventually released unharmed on Sunday.
   Why did the AU team take pictures of the bodies?
hypothesis: Local residents insisted