Malta Caves, missing children, strange animals

I come from Malta and as a young boy / teenager I visited the Hypogeum several times. But never heard the school kids story.I am sure it must have happened though.Trying to get friends in Malta to tell me more...
A bit of news came out two weeks ago.The government has just passed ownership of large parts of underground works in Valletta itself to local heritage group.
Let us hope this will be extended to the whole of Malta.
But even many years ago there were at least 22 miles of tunnels collecting rain water .
The whole Island was one big military base and they always dig.
My guess is the kids fell into man made tunnels and these would have air vents..and sound would come out of these.If tunnels are secret ..air vents would be hidden.
Now the "humans" in the tunnel were probably cautioning the young lady to stand still because a large snake / creature was next to her.