If Peeta fell in love with Katniss before the games, Why did he help the others

[ManInNeed]

try to find her? So I just got done watching the Hunger Games and if its not obvious I haven't read the book so my question is (BTW there will be spoilers for the sake of the question so be warned) about when Katniss was up in the tree and saw Peeta helping the other people find her but then just shrugs it off like it was no big deal and the movie Never Brings It Up Again. I was under the impression she ignored it as a survival strategy (strength in numbers) up until the end of the games when she refuses to kill him and win. Does the book go into any more dept on the whole "Lets kill my crush" Scene?

 

[sierra]

He joins the group of other people so he can make sure they don't kill Katniss. They explain it alot better in the book. He joins the group so that when they find her in the tree he can say "Oh, leave her there. She'll have to come down eventually." That gives her time to think about what to do to get away Also, since he joined the group of strong people, he wouldn't be killed off right away, so he could live longer and protect Katniss longer

 

[RedLucy]

He didn't do it to help them find her . Peeta does it to actually prevent them from finding her. So if they did eventually come across her, he could somehow protect her. Also, to gain their trust .

 

[Alex]

Because they would have killed him if he didn't (and I think he was planning to betray them anyway, after all he convinced them not to kill her when she was in a tree and he helped her escape from them afterwards anyway).