There's a problem with connections from the Siberian site to the mysql database hanging around on the database forever.
Searching through the code, I see it's using PDO to connect to the database. A variable called $dbhCon is the PDO connection object. A variable called $dbhQuery is the query that is executed. The only instance I can find of $dbhQuery->execute() is line 16 of /include/search-results.php. The results of that query execution wind up in a php array called $rows. I've added a $dbhCon = NULL; line immediately following that assignment in an effort to force the connection on the mysql database to terminate, as it sometimes seems to hang around for weeks.