What is the definition of Qasamah? And what are its rulings? Thank you.

In jurisprudential terminology, Qasamah refers to repeated oaths sworn in a murder claim. These oaths are sworn by the victim's guardians to prove the killing against the accused, or by the accused to deny the accusation. Through Qasamah, in cases of intentional homicide, either Qisas (retaliation) or Diyya (blood money) is established, though there is a difference of opinion among scholars on this point. In cases of accidental killing, Qasamah establishes Diyya payable by the 'Aqilah (male relatives on the father's side) of the killer.