Answer:
After Peeta was moved another Capitol propo, Katniss noticed that he has lost weight and developed a nervous tremor. Katniss noticing Peeta's condition, she realizes that he has been tortured.
Peeta tells Katniss that she's being used as a weapon.
Explanation:
In Chapter 8 of the Book 3 of the Hunger Game, Mokingjay, Peeta was moved to another Capitol propo.
When Peeta's video was broadcasted, Katniss noticed that he has lost weight and developed a nervous tremor. Noticing Peeta's condition, Katniss realizes that he has been tortured and that his video was taken just after he came out of the arena.
In his interview, he tells Katniss that she has been used as a weapon by the rebels. He asserts that she's been used by the rebels to destroy all the humanity. He asks her question if she trusts the rebels.
