I'm searching for the song when the female titan kills the 2 guys then goes to Armin (It's the episode 17 of Attack on Titan season 1). I tried searching on YouTube or in the theme itself of the female titan but nothing.
It's a part of 進撃st-hrn-gt-pf20130629巨人 from Attack on Titan Season 2 OST.
There is a YouTube video that cut out the part to make it standalone.
Originally a part of "Shingeki st-hrn-gt-pf20130629 Kyojin" from the Attack on Titan OST, this part of the song was cut out to be standalone.
It plays during the first appearance of the female titan in the series.