De acordo com Wikipedia :
[Twilight vampires] are immortal and difficult to destroy, only permanently killed when dismembered and then burned, as their body parts continue to move even after being detached.
De acordo com o Wiki da Saga do Crepúsculo :
In the Twilight universe, vampires are not known to be killed by human effort, are unharmed by sunlight, garlic, holy water, silver, any kind of stake, cross, and can enter homes without permission. Also, any kind of human weapon, including bullets, bounces off of them without any pain or harm done. The only known way to kill a vampire is to dismember his or her body and burn the remains before it can reconstruct itself. Thus their weakness is the strength of their kind or something as strong, which cannot be copied by humans, and fire that consumes them.
In the films, vampires are more vulnerable as they can be killed by severing their heads or biting it off their necks. However, fire is still the only known method to destroy them completely.