As it obvious there Should be Some layer two and layer one (physical layer tapping devices) network devices in between that we cannot trace or identify but they have an important impact on the result
These layer 2 & 1 network devices have many roles, including security issue. There are many Agency or Organization they capture data inphysical layerorData link layer.
As it shows some hop counts in the trace-route results, but there are certainly more L2 & L1 devices in the middle. I am looking for theory or practical way to find an answer for this question that can prove or identify data capturing.
AFAIK.. there is no way can find unless you control 100% pointA ->PointB - in which case you got complete control on entire path and devices in the path (+ physical access control). The technologies you use 1. L1 encryption 2. VPN. However L1 encryption is more efficient. Search online and you'll find more information (including some L2 encryption etc).