My guess is as good as yours
I know that sometimes one agency will seek help from another because they might specialize in certain areas, have info that they don't have yet or
maybe thay are just too busy to do it at the time.
I think that the people who took the records might have been involved in some other stuff or investigations that the USSS might already have a case
on......who knows?
But clearly the secret service does handle some aspects of
computer and telecommunications fraud, false identification documents, access device fraud, advance fee fraud, electronic funds transfers, and money
laundering as it relates to our core violations

Which this crime fits into the categories above....
They do alot more stuff than what most people know about.