Sorry to hear you went through this, op, and you did an incredible thing for someone in their last moments.
In answer to your question - objectively, I'd look at this almost in the same way as protocols for people seeking information about adoption (in the past, moreso than today where life story work is considered so much more fundamental).
So in the same way that a parent who had given up a child could make Social Services aware that they were receptive to contact, but would not make contact themselves.
Thus leaving the adopted child free to make those enquiries themselves, without any timescale forced by the other party.
The reason I say this is - I think if the bereaved partner right now wanted to reach out to you, she could probably have already made those enquiries with the police. And it seems she hasn't.
If she wants contact with you it needs to be on her own terms. So I would say make the police know that you are happy to be contacted and leave it at that.
Also, I know that you are an HCP but in my experience traumatic things that we can cope very well with at work can be a very different experience indeed when we experience them in our personal lives (and I noted that your son was with you, so you would have had to manage his own reactions as well as yours). So please do seek counselling support if you feel you need it, I'd imagine there's an EAP where you work that can refer you.
I think you did an incredible thing and I hope you have a happy christmas.