Source Reference:

• Component: BuddyPress:: bp-groups

  File: /bp-groups/bp-groups-forums.php :: Trac Source Line: 245

   * @param int $post_id The id of the post you want to delete
   * @param int $topic_id Optional. The topic to which the post belongs. This value isn't used in the
   *   function but is passed along to do_action() hooks.
   * @return bool True on success.
   */
  function groups_delete_group_forum_post( $post_id, $topic_id = false ) {
  	global $bp;
  
  	if ( bp_forums_delete_post( array( 'post_id' => $post_id ) ) ) {
  		do_action( 'groups_before_delete_group_forum_post', $post_id, $topic_id );
  
  		// Delete the activity stream item
  		if ( bp_is_active( 'activity' ) )
  			bp_activity_delete( array( 'item_id' => $bp->groups->current_group->id, 'secondary_item_id' => $post_id, 'component' => $bp->groups->id, 'type' => 'new_forum_post' ) );
  
  		do_action( 'groups_delete_group_forum_post', $post_id, $topic_id );
  
  		return true;
  	}