You're right, it is hard to believe, why would the person with the upper hand (eg manager) go berserk rather than the person whose friend had been sacked, much more likely to be the other way round. As its a report of a report and its in a newspaper, probably about the only thing that will turn out to be correct is that someone went to a restaurant.

In any event, I would hope that BA would handle it exactly the same way any other incident of this type between staff members is handled, which is, presumably first let the police enquiry take its course and then after that whatever internal procedures are relevant apply?