Can an adult be killed using the Death Note, by remembering their childhood face while writing the name? To kill a person using the Death Note, you are required to think of their face while writing their name. 

If the Death Note user last saw a person decades ago when he was a child, but has no idea what he looks like now, can he kill the person by remembering the childhood face?
This is never really explained, but according to the rules, you should be able to kill that person, if you know their name and face.

The human whose name is written in this note shall die.
This note will not take effect unless the writer has the person's face in their mind when writing his/her name. Therefore, people sharing the same name will not be affected.
           
— Death Note, How to Use: I