I was reading a bunch of articles in the Crime Library site and in it, they had a few people who were caught poisoning when the remains of the cremation were dug up and tested for thallium and arsenic. It seems the amount of those metals was too high in the cremation remains to be normal.
I was wondering if other evidence survives the remains of a PROPERLY cremated body. Note I use the words properly, 'cause I know DNA can survive a fire, but I don’t think it survives a cremated body.
Well, any sort of heavy-metal poisoning would show up, as would most radiotoxins. Other than that, though, if the cremation is hot enough, you could probably burn away any other evidence.
The “hot enough” is an important qualifier, though. I don’t know how thorough a typical cremation is.
It seems possible that a medical implant might retain evidence of physical trauma, though a pretty long shot for a) the implant to actually get damaged by any trauma, and b) the damage to be useful evidence. But I don’t see why, in theory, some CSI-nik couldn’t say “Look, these scrape marks on the victim’s artificial hip match exactly the serrations on the suspect’s custom-made bat’leth!”
This doesn’t fit the OP, but I understand cremation facilities harvest a fair amount of dental gold from ashes…
Implants are normally removed prior to cremation. Titanium burns really damn hot.