No. I didn’t think it then and I certainly don’t think so after 4 years of nothing.
Moslems don’t do secretive. They like a big bang that everyone knows about. No guessing, no spy-like cloak&dagger. Even if it was kind of “quiet” some Moslem group would’ve proudly claimed it for their own.
It’s not a Moslem problem.
Egyptair 990 was..