Enables you to search in comments separetly from the search loop.
This is a lite version of plugin Plugin for search in comments. The plugin you are looking for. It's search through comments. Can be added to page automatically or manually with shortcode < ?php if(function_exists('wp_sfc')) wp_sfc(); ?>. It returns comment author name, comment content and date in "times ago" format. Output can be styled with css.
If you like it and want other features to be activated, please grab it from here.