Can't delete .tmp files from file server. Access Denied

There are a handful of .tmp files on a 2008 R2 file server that I can't delete. The files look to be created by excel but I'm not 100% sure that is where they came from.

Here is what I've tried so far (Everything below is with administrative rights):

• Delete locally from explorer makes the file disappear but it comes right back
• Delete locally using an administrator command prompt produces access denied
• Delete remotely over the network causes file to disappear but it comes right back
• Try taking ownership produces access denied

Rebooting the server does allow me to delete the files but not a very good solution. Any ideas on how to delete without rebooting the server?

Thank you

Jacen