The last episode of School Days has been removed from the airing schedule on several different stations. According to the official School Days website it is unknown if they will allow it to be aired. A while back, it was announced that School Days might have a tragic ending as in the games that it was based on, which in were very bloody. The reason for the episode being removed has been confirmed to be due to a 16 year old killing her father with an axe.

Source: ANN | RandomC | Yahoo News (Japanese)

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It turns out that there is an article related the killing... it seems that she changed into a black dress just before killing her father

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Edit: Higurashi thread merged to this one

There are now reports that the next episode of Higurashi no Naku Koro ni Kai has been delayed. In the first season, there were several violent deaths, some of the victims were killed by axes. Higurashi currently in it's second season aires on five different stations, but their future plans for the show are currently unknown.

Source: ANN | Oyashiro-sama (Japanese) | Tokai TV (Japanese)