It is reported about Sayyiduna Ali (may Allah be pleased with him) and Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) (that both of them said): Deliberate killing is that which is done with a weapon.
Al-Tabarani recorded it. Its chain is broken (munqati') between Abd al-Karim al-Jazari and the Companions, but its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الديات / 10720