Missing logic files

Help anybody !!!!!

I had 5 gb worth of logic pro files stored on an external freecom drive. The drive is formatted as FAT32 as I have PC stuff on there as well.

I took my external drive round to my brother in laws to finish of some recording.

Plugged the drive into his iMac, opened the external drive and dragged the logic pro files onto his desktop, files appeared on his desktop and then disappeared, gone !!!

No delete button pressed, the files have gone from the external drive and we cannot find them on his imac.

Has anybody got any ideas where they might have gone ???? some hidden folders ??? and why it has happened.

Wait for it this was the only copy of the files.

The only thought I had was they might be still on my mac book pro but I have emptied the trash bin recently. Is there a way of getting the files back

Any help would be appreciated, yes I have learnt a lesson