Notice that all the inputs came from this address: 15TEAwEMxVS3BK718HhwgJg7nxwyJ2ib9y. I'm pretty sure if you go backwards you can land at DPR's other accounts.

Also, I don't think DPR just spent it (to someone elses address) as the trail has only addresses that were used for mixing... all the intermediate addresses have exactly 2 transactions... 1 receive from previous mixing address and 1 to the next mixing address all the way to its destination 1933phfhK3ZgFQNLGSDXvqCn32k2buXY8a.

The script I wrote followed a path that had addresses with only 2-10 transactions.
So lets break in down:

DPR's known address: 1LDNLreKJ6GawBHPgB5yfVLBERi8g3SbQS
Tumbler's receive address: 1BG9jDV3pA1MsJUnvRyWuA2b7PfGd4MZaw (only 2 transactions)
Tumbler's next mixer address: 12h6TzwPNBvDnppbsqpyXwW4oo5UUKaKSa (only 2 transactions)
Tumbler's next mixer address: 1EG9HJG9aGqzgGujfNQMiNbyqpKnFxafvE (4 transactions but note that the only output is to 1AHki5AbZYiz4fHkGSTVKN3T1Tv5PwZpnh... the remaining transactions are just too small -> this address may have been reused by the tumbler)
Tumbler's next mixer address: 1AHki5AbZYiz4fHkGSTVKN3T1Tv5PwZpnh (only 2 transactions)
Tumbler's final mixer address: 15TEAwEMxVS3BK718HhwgJg7nxwyJ2ib9y (7 transactions -> Note that this has only one output)
Final Destination address: 1933phfhK3ZgFQNLGSDXvqCn32k2buXY8a

There is no other path followed by the tumbler. So possibly the service used by DPR was pretty weak or probably he just manually mixed it himself.