Work items assigned to the position

[Chintamaneni,Rammohan,GLENDALE,BIS - SAP Workflow]

Hi All,
We have a situation where users were assigned to the position. Later user
assignment to the position got deleted on purpose. How do we find out the
old work items assigned to that position when there is no user assignment. I
tried using SWI5 with Position , but it didn't work. Your help is greatly
appreciated.
Thanks
Ram