ānantarika-kamma: the 5 heinous 'actions with immediate destiny' are:
killing an Arahat (Saint),
wounding a Buddha,
creating schism in the monks' Order.
In A.V. 129 it is said:
"There are 5 irascible and incurable men destined to the lower world and to hell, namely: the parricide," etc. About the 5th see A.X. 35, 38.
With regard to the first crime, it is said in D. 2 that if King Ajātasattu had not deprived his father of life, he would have reached entrance into the path of Stream-entry (App.).