For a while now, I have been pursuing my theory of residual data stored in Ethernet Cables. Unfortunately, I only have access to primitive equipment and detection gear. Nothing like the US government must have. Still, even with the primitive gear, I have been able to detect faint shadows of residual data lingering in Ethernet cables. This is mostly detectable when the cable is still plugged into an Ethernet switch port on a switch that is still powered on.
The fragmented bits are hard to reassemble and I don't have the technology to extract and assemble the data into decipherable blocks. Still, it look very promising to be able to peel layers of data off the cable and eventually use it to find information left behind by the users. It would even be possible to eventually locate passwords and secure access credentials from these cables. I fully expect that cables that are disconnected and put in a closet can one day be used to extract stored data. This is really exciting research. A little scary too!