I think someone is yanking your chain so to speak.
I have made about 3000 dives in malta over the last 36 years and I've never been lucky enough to see a shark there although last year I did see a Echeneis naucrates (shark sucker)in Anchor Bay (Popeye Village to some).. it's the closest I've seen to a shark in Maltese waters.
The one mentioned at Għajn Tuffieħa and St Georges Bay last year is accredited as a mechanical shark being used by a foreign film company for a documentary... The report was due to it being a slow news day.
Officially Jack Smedley was killed by a White Shark at St Thomas Bay Malta on July 20th ......1956
I think what you've been told is a bit like the "there's no aligators here .. the crocodiles ate them all" story.