What I would like to know is:
1. What would be police procedure? Do they first make sure she's all right, and once they discover she is do they question her then and there? What sort of questions do they ask? When she can't answer them because she claims not to remember, what do they do next? Do they bring in a psychiatrist?
2. I'm pretty sure I've got it covered how one would go about diagnosing her. But I read somewhere that if they needed her to recover her memory right away they could try hypnosis and drug-facilitated interviews, even though it may not always work. Would the police insist on this? Or does it have to be voluntary?
3. How long would all of this take? Where would she stay during all this? A hospital?
4. Once the police learn the woman really is suffering from dissociative amnesia, what do they do next? Can they do anything, especially if a body hasn't turned up and no one has come forward? I'm hoping it would be okay for them to let her go.
5. Would therapy be required or voluntary after she is released?
And, just in case I'm completely wrong, it is dissociative amnesia my character has, right? I've googled it and read various website articles, so I think it's the one I want. Not only does she not remember the past two years, she doesn't remember anything about the people involved, even though two of the people directly involved were childhood friends. But she should be able to remember eventually. Maybe a bit cliche, but I've got tricks and sleeves! And those tricks happen to be up those sleeves!
I've looked under the "police procedure" and "amnesia" tags and googled "dissociative amnesia" and "police procedure amnesia".