Unable to delete an invalid download file

MacBook Air, OS X version 10.9.5

Safari 9.0.1 (9537.86.2.7.2)

I'm not sure of the sequence of events that caused this condition, but I have a "Safari download" file that occupies zero bytes on disk (according to Finder/Get info) that neither completely downloads nor can be deleted (aborted). The file's icon shows a progress bar that is 75% but won't complete as it is now invalid. The file can be put in the Trash, but cannot be emptied from the trash. The Trash message indicates, "The operation can't be completed because the item "8Nov15_2.pptx.download" is in use." Regardless of whether I press the Stop or Continue buttons, the file remains in Trash. It appears that the file will never finish downloading because the operation cannot be resumed on an invalid file.