Arsenal needed to win, but that wouldn't have been enough. They also needed Totenham to lose or draw.
So when the Totenham team all gets food poisoning the night before the biggest match of their season, and can't get the match postponed, then I suspect foul play. I'm not saying that Arsenal FC was involved, but it could have been an overzealous Arsenal fan working at the hotel, who saw a 'golden opportunity'.
While the police are looking into the incident, they are not investigating it (which as far as I'm concerned is pretty confusing!) as no allegations have been made. . But if they find that there was foul play involved, Arsenal should be banned from European football or something.