GroupShareKit Delete a TU from a TM

I am trying to delete a Translation Unit belonging to a Translation Memory by using the GroupShareKit. I can see that the GS API exposes a DELETE method with the exact purpose. I managed to delete all of the contents of a TM. I see that there is a filter option present, but I cannot figure out how to use it. Is it possible to delete a TU by using the TU Id? Or is there another way to use the filter expression to uniquely identify the TU I want to remove?

This is a request to the GS API I made from Postman:

If I leave out the filter expression from the body, the entire tm content gets deleted. But with the current filter (shown in the picture above) there is no effect. Is there a way to achieve this?