Problem with deleting Autopsy case files

Dear all,

I have been using autopsy to try and recover some deleted .VOB and .avi files from my external FAT32 usb drive. Autopsy created a folder in /var/lib/autopsy with the case name, in which it put other folders with the names images, logs, mnt, output, reports etc. in which are contained different files with information about the deleted data restore and with one file in particular called sdd, which is quite a hefty file and has filled up all the disk space, meaning open office cannot even open without giving me a warning of no more disk space left.

I want to delete these files and folders created by autopsy. I have now manages to change the permissions using the following commands:

sudo chown username /directory

chmod ugo+rwx /directory

I did these two things, and then went to file properties, and turned on all the necessary tabs to permit read and write etc, but I still cannot delete these ruddy files!

Please help!

Thanks.