If the disappearance of MH370 was caused by suicide of one of the pilots and his goal was to commit the "perfect suicide", to disappear without a trace and leave the world mystified, then we will probably never find out.
We have no clue where the plane is. The pilot might have ditched the plane in a controlled way to avoid breaking it apart and any floatable parts separating from the aircraft, and then let it sink as a whole in a remote and deep part of the ocean.
If we ever find it, we will most likely find that the CVR and the FDR had been disabled before the events started.