It wasn't hard to prove the existence of a hacker.
The Naran's family special hacker always recorded the inside of the network data world whenever he went to do a mission.
This way, if he were killed or injured, his friends would be able to watch the surveillance video and know what to do to save him.
To record things inside the network data world and to be able to capture one's consciousness image, the hacker needed to buy a costly program that also required a monthly maintenance.
The Naran Family's hacker was obviously rich enough to afford this kind of program. After all, this program is essential for all professional special hackers.
Thus, after receiving Paul's permission, the man checked the software he planted inside the computer that he used to connect to the network data world and proceeded to extract the surveillance video.