Erwin Schroedinger said
The last time I counted, there were two pilots in an airliner cockpit. Why is the Captain the only pilot under suspicion? Why has the F/Os home, hard drive etc not been searched? Why is he not stated to be under suspicion? Why is he not 'a pilot'?
The answer to that, sadly, might be this
The son of a high-ranking official in the public works department of a Malaysian state, Fariq joined Malaysia Airlines when he was 20.
Now I will say, reports are his home was also searched. (as seems to have been addressed by others)
But that quote might possibly give some indication as to why more official attention seems to be paid to Zaharie Ahmad Shah rather than Fariq Ab Hamid. It might also be why the prior against-policy actions of Fariq seemed to have flown so far under the radar as to not only apparently result in a lack of discipline, but even seemingly proved no resistance in his resent promotion to the cockpit of a 777.
(this works off my belief that the incident with the ladies/smoking can not be a one-time thing, and that the airline had to have been aware at some point. I could be wrong, of course, but...)
That said, if I had to pick one of the two as being involved, I would go with Zaharie. Mainly because of that initial sharp Ascent/Descent and the skill it likely would have taken to pull it off seemingly rather smoothly (even if was not as extreme as reported, it was still drastic.) Was Fairq experienced enough to do that? Then add in all the radar avoidance tricks and all... And on second thought, stuff such as that could be playing a huge role in their seemingly leaning towards Zaharie as well.