I can assure you this certainly did happen as I was a passenger on the plane.
Remember four years have passed and some details can become hazy, or as so often happens in these situations, minor details can grow. The police may possibly have been airport security?
For four years I have searched the internet for info, and as you have pointed out nothing appears anywhere regarding the incident.
Somebody told me back in Dublin that there was a short item about it on Sky News. I've also checked their web and not found anything so I don't know if what the person in question saw referred to my incident.
I remember the date clearly as my afther fell very ill the day before, we thought he was dying (I am happy to say he is still with us, yet suffering from a very rare lung problem). I found out on the evening of Feb 21 and the only flight I could find from MAD was this one via Frankfurt.
I remeber one German passenger saying that there had been a number of incidents at the time in Germany, and he felt the reason they were trying to get us straight onto another plane was to avoid the news spreading. I know and hope their is no truth in this at all.
I sent a letter to Lufthansa after complaining about how we were treated. The rapidly returned a letter of apology (confirming the incident) and telling me they hoped and looked forward to me flying with their airline again.
The indicent, as you said possibly "only" an engine fire which may not be serious, but as a passenger it can be a horrific experience especially when treated so coldly by the staff.
Anyway, thanks and if anyone out there know anything I'd love to know.