Continuity mistake: When Boggs and the team approach the area to film the first propo, we see them approach the square from behind and the ground is dry. Camera changes to the front and now the ground is wet. (00:45:40)
Character mistake: In the exchange at the train station in district 2, Katniss says how she killed Cato in the 74th games, and Cato killed Thresh and Thresh killed Clove etc However Cato didn't kill Thresh - he was attacked by the mutts and killed by them. (00:14:50)
Answer: Coin was ultimately responsible. Coin sent Prim to the Capitol and then had the Capitol bombed. The rebels, led by Coin, used hovercrafts with the Capitol insignia on it to drop the bombs so that the public thought it was the Capitol bombing their children. Coin wanted Katniss to blame Snow for Prim's death to get her full support.
Bishop73