Not sure if I have understood correctly, but I thought that the OP meant that they did not want to mention any names in regards to this family in case there are living family who may find this thread and who perhaps either did not know about the murder or may not want anyone else finding out.

Xpq194z, yes, you can buy the death certificate without involving any of the family.
If you can find the death here:
https://www.freebmd.org.uk/cgi/search.plYou can apply and pay via the GRO website:
https://www.gro.gov.uk/gro/content/certificates/login.asp but you do need to register.
Good luck.
Added: there may be reports of the murder and trial in the local or national newspapers of the time. I think many have been digitised and viewable online via subscription. If you start a new thread requesting a newspaper lookup you may find that someone is able to do this for you via Personal Message as you do not want to give the names on this public forum.
