SPpolicy_purge_history Jobs in progress for more than 9 hours. How to kill the step?

Dear All,

I open the Job history and found that sppolicy_purge_history job was in progress for more than 9 hours and still its in progress. I stop the job but it still in progress.

The step 3 is not able to get completed. Which is Erase Phantom System Health Records having following script.

if ('$(ESCAPE_SQUOTE(INST))' -eq 'MSSQLSERVER') {$a = '\DEFAULT'} ELSE {$a = ''};
(Get-Item SQLSERVER:\SQLPolicy\$(ESCAPE_NONE(SRVR))$a).EraseSystemHealthPhantomRecords()

My question is how to stop this step and why it is not able to get completed?

Please provide your help.

Thanks.

Azwar