Whilst it's a terrible thing to have happened, and something that I wouldn't wish on anybody, as far as I can see (and from the info provided in the description), they were all left together in a van.
That's asking for trouble, however I hope they all get found and returned.
Hopefully they'll learn from their mistake next time and put the bikes in a more secure location. Of course there could be a perfectly good reason why they were left in the van - I'm just going by the info provided.