‘Alee’s Ruling On Killing Those Who Fabricate Hadeeths
According to Amir al-Mu’mineen ‘Ali ibn Abee Taalib, the discipling punishment could reach the level of execution if the crime was very serious and had a far-reaching impact.
One such crime was fabricating hadiths and attributing them to the Messenger of Allaah (saw), because this action leads to introducing things into Islaam that are not part of it; this causes people to deviate from the religion that Allaah (swt) chose for them. Hence he used to say:
“Whoever tells a lie about the Prophet (saw), strike his neck.”
[The Life And Times Of ‘Alee, by ‘Alee Muhammad As-Sallaabee, p. 534]