When handling a smart device that is powered on, what initial step should be taken?

When handling a smart device that is powered on, placing the device in airplane mode is the most appropriate initial step. This action effectively disables all wireless transmission capabilities, including cellular data, Wi-Fi, and Bluetooth, which helps prevent any remote access or data encryption that could interfere with an investigation. This is crucial in scenarios where maintaining the integrity of potential evidence is essential, as data can be altered or wiped if the device is online.

Locking the device may restrict access to its contents but does not prevent remote actions or modifications. Rebooting the device could alter data in memory and impede forensic analysis. Removing the battery, while it could halt any ongoing processes, may not be feasible for all devices, especially those designed with non-removable batteries, and could lead to further complication in retrieving data. Therefore, initiating airplane mode is the optimal first step to safeguard evidence.