How to find who has reopened a Batch

Hi,

This is though a functional issue, still request came to me for a help on reopening of a posted batch which is showing in error since long Under P0011.

As per my Layman understanding if some batch is in error, unless it is reopened and worked with , month end cannot be done.

So my primary question is how can I find who has reopened the batch??

And also the users who has posted these error batch are no more with the organization. So how can I check on the reason for the error.

BR,

Jyotirmoy Roy