Shooter is also dead.

So, no one to interrogate. Convinient.

I presume from superb owl that you are from USA.
No. It was deemed legal and fair use as was recording radio on c-cassettes.
Considering digitizing, Web stores are full of usb capture dongles and rca/scart adapters. Obs and Videolan are free and easy to use.
For editing, Openshot is free and quite easy to use.
All these are available on Windows, Linux and Mac.

Evidence or “We swear this was filmed under UNRWA headquarters. Trust me bro.” ?