Parashas Masei · Passuk 35:21 · TT note 2
Chabad.org — English translation + Rashi
Torah Temimah points to Sifrei (TT note on “הִכָּהוּ בְיָדוֹ”).
English: “He struck him with his hand” — why is “with his hand” stated? Because Scripture says “if he struck him with an iron implement… or with a hand-stone or with a wooden hand-implement,” I have only [liability for] killing with these; from where [do we know about] one who crushed, strangled, kicked or crushed him? Scripture says “with his hand” — in any case.
Expansion of “hand” to any direct bodily act that kills.
Crushing, strangling, kicking or similar direct physical acts that kill are capital murder under “he struck him with his hand.”