Who is the Torah talking to?
Targum Yonasan: To Klal Yisrael.
What is the Pasuk coming to teach us?
Rashi: It teaches us that if, after the calf's neck has been broken, the murderer is subsequently found, he must be sentenced to death. 1
Seforno: It teaches us that although they have placed the onus of the Kaparah on Hashem, that is only because they do not know who the murderer is, but there where they do, it is preferable to carry out the death-sentence themselves. 2
Riva and Rosh: It teaches us that if they do what is straight in Hashem's eyes - the judgment of murderers, the Eglah Arufah and the measuring - witnesses will come and the murderer will be revealed [and sentenced to death].
Kesuvos, 37b: The Pasuk is comparing all murderers to the Eglah Arufah 3 - to teach us that they are sentenced to death by the sword (Hereg).
Rashi: Which is the correct thing to do (as the Pasuk concludes). See also Torah Temimah, citing the Yerushalmi Sotah, 9:6 and note 67.
In keeping with the Midrash Tanchuma in praise of Beis-Din performing justice - 'If judgment is carried out below, it is not necessary to carry out Din (Divine retribution) above'.
See Torah Temimah, note 66, who attributes the D'rashah to the Gezeirah Shavah "mi"Kirbecha" "u'Vi'arta ha'Ra mi'Kirbecha".
Why does the Torah refer to removal of 'the innocent blood' and not 'the murderer's blood'!
Riva: Because it is referring to the victim's blood, which, once the murderer is found, will stop bubbling and become still.
