Formal:
* Physical anthropologist specializing in forensics
* Bioarchaeologist with forensic applications
* Skeletal specialist in forensic science
* Human osteologist in a forensic setting
Informal:
* Skeletal detective
* Bone expert
* Forensic bone expert
It's important to remember that "forensic anthropologist" is the most precise and widely recognized term, so it's generally the best choice unless you have a specific reason to use a different phrase.