Wow, I never wanted to work in a company where I had to say this. Really, if the pay grade decides which human you are, I better get no money but can do whatever I want, like go to that person, ring on its door and ask it about its plans.
This guy clearly was following that and did his due diligence of step 1 being, make a backup of the device. Then you have a record of everything as near time of discovery as possible, so if you're investigation hoses everything up, you can restore and start over.
The author is also correct in that once he's done his investigation, he passes it all on to the next level to do their job. So in his case, he's done. There is NOTHING else he should be doing. If he does it really could hose up any/all legal action.
Kinda like getting to court in a Sexual Assault case and finding on the arresting officer forgot to read the guy his Miranda Rights.... You can have 100% proof this is the guilty party, but he goes free because someone in the chain of custody hosed up their part.