The Victims section of this website gives a regional breakdown of all currently known mental health homicides.

The listing for each individual case should give an indication of whether an independent investigation or inquiry has been held or not.

If an electronic version has been published the inquiry report can be downloaded directly from the listing.

If there is no electronic inquiry report hard (paper) copies should be available from the Strategic Health Authority or the local mental health trust concerned

A list of Mental Health Trusts is here.
http://www.nhs.uk/servicedirectories/Pages/MentalHealthTrustListing.aspx

Details of Strategic Health Authorities are available and as a list here.
http://www.nhs.uk/servicedirectories/pages/strategichealthauthoritylisting.aspx