"Officials narrowed their search for the family after learning that Ken Martin had used a credit card to buy gas at a station near Cascade Locks, a small Columbia River community about 40 miles (64 kilometers) east of Portland."
Credit cards were new technology in the 50s.
"American Express was the first issuer to offer a plastic charge card in 1959, and others soon followed." https://money.usnews.com/credit-cards/articles/the-history-of-credit-cards
"Officials narrowed their search for the family after learning that Ken Martin had used a credit card to buy gas at a station near Cascade Locks, a small Columbia River community about 40 miles (64 kilometers) east of Portland."
Credit cards were new technology in the 50s.
"American Express was the first issuer to offer a plastic charge card in 1959, and others soon followed."
https://money.usnews.com/credit-cards/articles/the-history-of-credit-cards