How to find work item id based on idoc number

Hi Folks,

When we open work item id's in SWIA tcode we can see error message related that particular w.id, in our case usually we get contract number and idoc with the error text.

My requirement is,

1) I want to find work item id based on idoc

2) which table store closed work items date, i mean status of work item id is completed

I gone through many threads, sap_wapi* Fm's, sww* tables but no luck. I left no stone unturned but no luck.

Regards,

Hari