shooting

In a test match there was an interesting stand. Maneater ogre captain is tried to shoot from an non elevated position trough an active melee fight (his second in command hunter and a couple of chaos hounds. Is is valid to shoot trough an active melee fight?

There are no rules to my knowledge regarding shooting through a Close Combat cluster. Though the cluster might grand the target Cover.
In my old group, we House Ruled, that if a model was the cause of cover, and the shooter missed by one on the dice roll. The model causing cover would be hit instead of the intended target! In your case a random model from the Close Combat cluster... So not without risk.