Not to mention drones that can read biometric data from considerable distance, and Israel has those biometrics because most of these jihadis have been captured by Israel previously and then released by some ridiculous liberal pretext. But not after gathering their biometric data.
If any leaders were held as prisoners they could have placed trackers as implants without the prisoner knowing (if the prisoner was drugged and knocked out first).
The tech exists today—here is an example: