Heard from Jacksonville Beach...
I just got off the phone with a detective in the Jacksonville Beach PD. She said she was glad to hear from me; they'd apparently lost or mislaid the contact information they had for me, and she wanted to tell me what was going on with my mother's murder. It's a cold case, (February 23, 1996) but by no means insoluble, at least from what she says.
She had a few questions for me, which I was able to answer. I've got Mom's old address book here, and will send her information about her relatives in the JaxBeach area, although I haven't heard from any of them myself in many years, and am not sure if any of them are still alive.
She confirmed that a black guy had been caught with jewelry that belonged to Mom; she said that the guy had maintained that he had bought the stuff from a couple of white guys who were known to the police in their own right. One of these guys is in prison up in the Carolinas at this time.
This sounds like a plausible line of inquiry to me. Particularly after her head injury, Mom couldn't understand that things you can do here in poky small-town Iowa aren't necessarily safe in places like Southern California or Florida. Her first winter down there, back in 1985, she found two guys living in an old school bus and let them move in with her in the spare bedroom of her condominium. Until she got home, I jumped ten feet whenever the phone rang, half-expecting it to be the same sort of phone call I actually did get the night of February 23, 1996.
As and when I get more information, I'll post it here. Here's hoping the case does get cracked.