Error Deleting Time Machine Backups

Question

I moved roughly 200 time machine backups into the trash. I appear to only have read permissions for these files, but didn't get an error when moving them from the backup drive to the trash. When I empty the trash I get the following errors:

"The operation can't be completed because the item {hard drive name} is in use."

"The operation can't be completed because the item {backup directory name} is in use."

"The operation can't be completed because the item Library is in use."

"The operation can't be completed because the item System is in use."

I am getting this set of errors once per each backup. It's deleting all the other files and directories associated with each backup. I need a way to delete the remaining folders.

I've tried opening the Trash and right clicking on the items and selecting Delete Immediately. It prompts me for the admin username and password. Then it gives me the error about the hard drive name being in use again. I've tried quitting all applications. I've tried relaunching finder. I've tried rebooting. I've tried opening up terminal, navigating to ~/.Trash and putting in rm -rf 2019-08-28-103432 and that didn't work either. When I navigate to ~/.Trash and type ls I'm not seeing any files or directories.

What can I do to delete these stubborn files?