Potential espionage indicators $($PEls$)$ are activities, behaviors, or circumstances that "may be indicative" of potential espionage activities by an individual who may have volunteered or been recruited by a foreign entity as a witting espionage agent. Examples of PEl include:

$($Select the best answer$)$

Unexplained affluence, Concealing foreign travel, Unusual work hours, Avoiding polygraph

Taking classified material home, Illegal downloads, Unreported contact with foreign nationals

Disgruntled employee, Attempting to gain access without need$-$to$-$know, Taking short trips

Copying files, Unexplained absences$,$ Terminating employment

All of these