Here is a link to the original report in the French media, which confirms that Commissioner Fredou was indeed working on the Charlie Hebdo case:

“The Fredou Commissioner, like all agents SRPJ, worked yesterday on the case of the massacre at the headquarters of Charlie Hebdo. In particular, he was investigating the family of one of the victims. He killed himself before completing its report. A psychological ‘cell’ was set up in the police station.”