they were mad when kakashi killed her and wanted to retrieve her bodyi dont think her bodu was so inmportan to be experementing on .... she looks like she's from the kiba klan ... a total fodder
LOLIt's because kakashi wanted to touch rin boobs end of the story
hmmm i see .... well who knows maybe she was , connected to something or was part of a clanthey were mad when kakashi killed her and wanted to retrieve her body