Is it permissible to pray for the killer of one's grandfather with good or with evil?

It is preferable for the wronged person to forgive and pardon in order to attain the reward of the righteous and the patient, as stated in the verses: "And hasten to forgiveness from your Lord..." and "So whoever pardons and makes reconciliation - his reward is due from Allah," and "But whoever is patient and forgives, indeed that is of the matters [requiring] determination." It is permissible for him to supplicate against the oppressor, based on the saying of the Prophet, peace and blessings be upon him: "Three prayers are not rejected: ...and the supplication of the wronged person..." And the supplication of the wronged person for good for his oppressor is among the signs of those with great fortunes.