In that situation, the evidence is all in electronic format. The government must backtrack and establish what computer was used, what accounts were used, to whom those accounts belong, or who used them.
The manner of evidence collection and the mode of the evidence, electronic or written, is different. However, it is still generally the same in that an individual could tie the person charged to a specific instrument, document, or transaction and establish that they knowingly intended to defraud the other party.