The following should not be cast on beasts that players are hunting: Any heal spell (or Vita regeneration spell), spells that reduce AC (such as Sanctuary or Harden Armor), or might-raising spells (such as valor). Doing so will endanger the life, and potentially kill, a player while hunting.
If sufficient evidence is provided that proves someone is using these spells on a beast, the charge is attempted murder. Any of the above, or combination of the above that results in a players death outside of a PK area will result in a charge of murder. Again, sufficient evidence must be provided to prove the charge.
Edited: Maiyu (Hyul 14)