A customer has come in and asked to dispute ATM and other transactions going back approximately 1 1/2 years. They have their cards. Per the rules as I understand them, we have gone back to the first disputed charge and calculated forward 60 days from the first statement showing the transaction. ATM video is no longer available for these transactions, but we have identified the account owners in 5 other ATM videos for more recent transactions that they also named in the dispute as being unauthorized. Since we do not have evidence to prove that they did the older transactions, can we use the evidence for the later ones also disputed to deny the whole claim?

You can use the "totality of information" available to you in your investigations, including the consumer's transaction patterns, etc. If you have what you believe is conclusive documentation that several of the disputed transactions were, in fact, completed by the consumer, I think you have enough reason to conclude that the consumer might be "mistaken" or "misinformed" concerning the earlier transactions, especially if the older transactions were completed at machines or locations where you have evidence the consumer completed some of the later transactions.

All of which is a "polite" way of suggesting that the consumer's entire claim is fraudulent. I suggest that you have enough here to deny the claim, cancel the card(s) and ask the consumers to take their account(s) elsewhere.