You should start with a victims' advocacy group in your area. They will be able to help you figure out what to do.
Crime Victims Advocacy Council - Atlanta, GA (770) 333-9254
I am sorry for your loss and good luck.
I am very sorry for your trouble. Your best bet is to contact the police agency in the jurisdiction your mother was discovered. Ask to speak to a homicide detective, or, call the office of the prosecuting attorney's office and ask to speak to a victim advocate.
If there is anything else I can do, I will be happy to talk about it further PRO BONO, which for me means 'for the good of it', and for you means FREE.
James Regan, Esq.