http://sports.yahoo.com/blogs/nhl-pu...145929531.html
The accuser has to convince a grand jury that a crime has been committed, and grand juries are hard to predict.
In the State of New York, a Grand Jury is NOT mandatory, and Kane could have been charged without this hearing.
From Wikipedia:
In the State of New York, while a person can initially be charged with a felony via a sworn written accusation alone (a "felony complaint"), the state constitution provides a defendant with a right to have all felonies prosecuted by way of a grand jury indictment. This right can be waived by a defendant