It was a checked luggage inspection following an alert by the CTX scanner.

Summarizing, the Court held that the inspection of the bag to clear the alert was permissible, but once the screener exceeded the scope of clearing the alert, evidence found thereafter was inadmissible.

Looking through photographs in order to clear an alert due to "dense" material, even though the content of the photos is observed, is permissible to ensure there were no "sheet explosives" within the photographs.

Here, the TSA clearly exceeded the bounds of an administrative inspection, but only materials found after the bounds were passed are inadmissible. Anything found before that line was crossed are still admissible as evidence.