I think there is too little information to make any deductions on WHAT exactly happened, but I have some observations,
1. The so-called "death" character. I'm in favor of it being accidental. Notice in the first case (10 year old one) there are some flowers near the bloody symbol? and in the current one there is an obvious cigarette nearby? I think that in the first one, the center of the character was covered with the flower and in the current one the center was covered with the cigarette. There is a space in that kanji (or japanese) where these items would fit in almost perfectly. To those who know the language here, what do we get if we fill out the space. Shown here,

(Forgive my piss-poor photoshop skills, I just created an account on imagashack just to show this out) Does anyone have any idea what THAT symbol could mean?
The ... problem I have with my own "deduction" is WHY Kudo's father would withhold the info? I have no idea at the moment.
2. Those who say that (what's his name?) was "brushing" his teeth, have a look at this scene again,

Notice how CLEAN the wash-basin is? No water flowing and no "spit" foam in there either. Something's funny, but I can't tell what.
Puzzled,
chronodekar