dstiles - 7:45 pm on Jul 10, 2013 (gmt 0)
Lucy - I had that range listed as MHost but yes, not currently allocated, it seems. It's possible it fell to the latest round of exploiter shut-downs - there has been a fair amount of activity in recent months, causing a flurry of new bot activity from those attempting to create more robust botnets.
Following up through ixquick and entering the starting IP brings up a result from nanog which states the range was hijacked last August from DonEkoService (which they say was dodgy anyway). Maybe it was just reclaimed by RIPE.