Asaji Mainichi was a petty criminal presumably killed by Kira.
Mainichi has short, dark-colored hair, a thin mustache and stubble.
Light Yagami assumes he may still be under suspicion by L if he only kills minor criminals seen on the news. He decides to openly watch T.V. in front of the cameras in his room, and discretely kill minor criminals. This way, minor criminals are killed when he's either watching or not watching T.V. Mainichi is one such minor criminal whose name is written in the Death Note. Light also remembers the names and faces of major criminals that he can kill later on when he isn't home.