In your showthread.php file look for:

if ($threadinfo[open]==1) {
$replyclose="$replyimage";
} else {
$replyclose="$closedthreadimage";
}

and change this to:

if ($threadinfo[open]==1) {
$replyclose="$replyimage";
} else {
$replyclose="$closedthreadimage";
$whoclosed = "This thread closed by $username";
}

then in your showthread template put:

$whoclosed

wherever you want it on the page.

Note: You will have to post the last message in the thread for the correct person to show up as to closed it as it lists the last person in thread as the closer. But this allows your mods to post the reason why it was closed and at the same time alert the author of the post who closed it.

Parker