Can deleted files be recovered on a bitlocker enabled device?

I received a 2 gb olympus sound recorder which I was asked to restore to normal fuctionality, and restore some mp3s that were presumably recorded on it.

The file system appears to be intact, so I can read from it, but there are two noticeable changes to the device.
First, it seems to have been infected with a version of the RECYCLER virus, which turned all the folders into links which point to the virus itself.
One of those folders are thought to contain the mp3 file in question.
Second, the device seems to have been bitlocker enabled, but it does not need any encryption key.

Now, I don't know, in what order did these events happened; I only need a confirmation, that no data can be recovered once deleted, either before or after bitlocker is enabled.

Thank you.
Turns out, the virus did not delete these files, it only made them invisible, so when the bitlocking event happened, those "hidden" files were also encrypted, and did not get lost.
Hurray!

btw. what I wanted to know is the details of the bitlocker file handling mechanism for a definitive answer.

I wanted to go further, but thanks anyway. This thread is closed.