The RER attack, again

I was wrong before - there are still no witnesses. They did not get anything from security tapes either.

I am starting to suspect that it either means that somebody really doesn't want those guys found, or that there never was any attack to begin with. In the former case - who? In the latter case - why?

There surely exist criminals that cover their tracks well, but I reckon the kind of thugs who mug people on a commuter train in broad daylight in front of twenty witnesses aren't exactly the criminal masterminds.

In any case the mind-boggling fact remains: in France you have to interfere in such a situation, and can get up to 5 years if you don't. If you do the sentence apparently depends on how successful you were.