So I recently lent my phone to my father. He broke its display and took it to a service center for repairs, all unbeknownst to me. I am kinda freaking out now because, only a few months ago, I had various nude photos of me and my girlfriend saved on its internal memory. Even though I deleted them before handing it over to my father, I am pretty sure they can be recovered using appropriate software. Is there anyway to check if such an attempt was made?
Model : Samsung Galaxy J1(2016) (pre-knox firmware)
Status : "unrooted" (checked immediately on deliver from the service center)
You're probably okay. If it was a few months ago, chances are the data has been overwritten by other files. If you're really worried about it, try DiskDigger. It needs root access for the best scan, but a basic one can be performed without.
Is there anyway to check if such an attempt was made?
No, there is no way to know if an attempt was made.
But to be honest, the chances this would occur are extremely low. Are you concerned your father may have requested they look for previously deleted files, then possibly it was done, but otherwise a shop is not going to waste it's time looking for random files, much less deleted ones, on random phones because there's more important things to do and if you ever got caught, regardless of what you found, you business is done.