dovuti uccidere

should have killed

→ dovere
phrase Uncommon #9,189
should have killed Used with a plural masculine object; the form changes to agree with the object in some compound tenses.
IT: Li avresti dovuti uccidere.
EN: You should have killed them.

Non li avresti dovuti uccidere.

You shouldn't have killed them.

Li avresti dovuti uccidere.

You should have killed them.

— Malcolm X (1992)

Non li avreste dovuti uccidere.

You shouldn't have killed them.

Non li avrebbe dovuti uccidere.

He shouldn't have killed them.