Four guys were caught using detectors on a farmer's field at night.
Initially the detector used in telescopes was the human eye.
"Countries with serious security problems do not solve them using metal detectors," he added.
We've got no realistic chance of using metal detectors on the doors.
The find has helped to improve the relationship between people using metal detectors and archaeologists.
Using detectors, the frogmen soon picked up the first one.
However, now, they have been using detectors to catch criminals hurting the park.
But new experiments, using better detectors, offer more convincing data that the phenomenon is real.
Guards at the door frisk you before they use metal detectors.
The system uses infrared and radio detectors to monitor unusual movement in the track area.