After touching the notebook...

[Persistence_of_Memory]

Okay...
After touching the the notebook, the Investigation team could see Ryuk. What if they went back and reviewed the tapes from the very beginning of the series when they bugged Light's house and he had Ryuk go and look for the cameras? Would they be able to see him or not?  

[mond -an- mitternacht]

Hmm... I have no idea. o_o

I'm not sure if you can see shinigami in past-recorded things...

They have no reason to go back and look at those tapes of Light's room, unless they suspected that, though.  

[Persistence_of_Memory]

[katgirl] Tsuki-chan

Hmm... I have no idea. o_o

I'm not sure if you can see shinigami in past-recorded things...

They have no reason to go back and look at those tapes of Light's room, unless they suspected that, though.

I don't know either. I don't think they mention it at all.

And it's a hypothetical question anyway.

Though, once they catch Light, they would be able to prove that he'd been acting as Kira from the very beginning by seeing Ryuk with him on camera. That's why they could go back to the tapes. Evidence.
 

[SCP-511]

I think they should have gone and reviewed all previous recordings of Light, but the investigation team wouldn't have thought of it, if L were there he would have figured that out and gone back to it once Ryuk was revealed. Perhaps in his spare time he had gone back to the tapes to look for Rem once he was able to see her, but since she wasn't there it wasn't mentioned.  

[Persistence_of_Memory]

Mokusei

I think they should have gone and reviewed all previous recordings of Light, but the investigation team wouldn't have thought of it, if L were there he would have figured that out and gone back to it once Ryuk was revealed. Perhaps in his spare time he had gone back to the tapes to look for Rem once he was able to see her, but since she wasn't there it wasn't mentioned.

Well, L wouldn't have known about Ryuk, so I don't think he would have really known to look. Maybe he wouldn't have looked for Rem either, since she only posessed Higuchi (as far as he knew) I don't know if L thought Rem could have been with the real Kira at any point. And I think Rem took L out before he could really think things over. I've gotta read that part over again...
And the investigative team probably wouldn't have thought about it...
I just mean as a retrospective kind of thing after everything was over.