Investigation horror films
 

I've been really into watching films about investigators/researchers/house 'cleaners'/etc. lately. I'm looking for some recommendations. I've seen a lot of them though. Er, not police or reporter investigations.

Here's some I can think of offhand that I've watched or looking through my netflix ratings:

Grave Encounters(blech)
The Haunting of Hill House(good stuff)
Paranormal Activity(disappointing)
Apartment 143
The Apparition
Oculus(only saw it for Karen Gillian, it was dull)
The Entity(so good, sound track too)
The various Amityvilles(number 4 was silly fun good, but not in the requested theme)
The Taking of Deborah Logan(decent)
Prince of Darkness(good stuff)
The Unnameable I and II(kinda loosely 'cleaning' filmes, but regardless great films)
Poltergeist I and II(very good I, can't remember much about II)
The Conuring(meh)
Stigmata(decent)
The Quiet Ones(decent, but leaning towards dull)

Ok so there's a list of ones I'm sure I've seen and can remember. Probably quite a few more I haven't listed I can not think of. OK, so can anyone offer suggestions not in that list? Much appreciated.

One of my all-time favorites:

1408

It counts, I think, because Cusack is a (jaded) ghost hunter.

Ty for suggestion. Already saw it and didn't like it.

seven? Though this might come under police and you have probably already seen it
Exorcist

In the Mouth of Madness, which seems to be my suggestion to everyone these days. ::roll eyes::

I actually haven't seen Seven, i'm not really into slasher/serial killer type flics.

Everyone's seen the Exorcist. : ) Me included. Ty though!

Seen it. So good. That was more police procedural noir/hard boiled investigation though.

edit: I have seen it, was confusing it with Lord of Illusions for some reason. Both great flics.

The legend of Hell House
The Haunting

The Legend of Hell House was already on my list, I just got the title wrong. Had it as The Haunting of Hell House.

Already saw the haunting, both are good films though. And ty.

Dead Silence. But I'm sure you've already seen that one.