Cinder Man, investigate the building

[Etrice]

So i have been all over the manor where it tells me to look and i can find nothing. Not even with the scaning thingy. i saw that their was like a hidden lab(or something) underneath the whole place with seemingly the only entrance being a door below that i cannot find the key for. so where dafuq do i go or do?

[DaZMaN76]

I think I lock-picked that door, but didn't have the level requirement when I first got the quest. I eventually came back later, when I had Lockpicking skill upgrades installed. I think I also tried when I just had Rank 2 +Thief armour upgrades, but they weren't enough IIRC.