Error in personae (mistake in the identity) - occurs when the offender actually hit the person to whom the blow was directed but turned out to be different from and not the victim intended. Unlike in aberratio ictus, there are only two persons present here: the actual but unintended victim and the offender.

Implications:

The criminal liability of the offender is not affected, unless the mistake in identity resulted to a crime different from what the offender intended to commit, in which case the lesser penalty between the crime intended and the crime committed shall be imposed but in the maximum period.

Example: A shot B who turned out to be his father whom he thought was B. Instead of homicide, it became parricide. In this case, Art. 49 will govern: error in personae becomes mitigating (apply maximum period of homicide as penalty).