What is the current state of the law on how to prove that a defendant obtained credit card numbers from a credit card skimmer?

Typical proof that a defendant obtained account numbers includes evidence that a defendant possessed cards or a document or digital file containing account numbers. See, e.g. , United States v. Onyesoh , 674 F.3d 1157, 1158 (9th Cir. 2012) (defendant in possession of a spreadsheet containing 500 credit card numbers); United States v. Gaussiran , 2018 WL 6528006, at *3 (C.D. Cal. Dec. 10, 2018) (defendant in possession of sixty credit and debit cards). Another way of proving stolen accounts is through evidence that the defendant used account numbers. See, e.g. , United States v. Alisuretove , 788 F.3d 1247, 1250 (10th Cir. 2015) (defendants made withdrawals from approximately 524 account numbers that had been obtained with a skimmer). And, of course, there may be other avenues of proof, such as expert testimony about the efficacy of a certain type of skimmer or the bank's experience in similar digital heists. Such evidence might bridge the gap between proof of trying and proof of succeeding.