I will play devil's advocate here. Kurin's osteological analysis was subpar for a forensic investigation. In each of the categories discussed in the "Fast Fact" sheet, she could have given specific examples as to why she determined that it was bone, human, etc. This would have further supported her conclusions. But I'll say she's not a forensic anthropologist, she's a bioarchaeologists. And bioarchaeologists aren't used to doing this type of work. Now to work both sides. These fragments are almost impossible to determine one way or another if no osteological landmarks are evident on the bone. Foramen, ridges, etc. would need to be used to determine the specific bone and that would help determine human or animal. She should not have said that they were human if she wasn't 100% certain. That's what I do. If I'm not sure, then I'll state that the evidence is inconclusive and further laboratory methods would need to be used to determine human or animal (histology, DNA, proteomics, ZooMs, etc.). Rick Snow's report doesn't state if they are human or animal either and he also states that lab methods would need to be used. I would counter his argument that the striations on the largest bone is older than 3 years. Considering this happened in a landslide, this could have impacts on the skeleton that would be consistent with younger than that 3 year marker. The DNA report was also subpar in that they don't definitively state that it is human or animal, they state that it's possible that it is cow. But, as you state, the possible human DNA evident on the bone could be from cross-contamination. But the opposite could also be true that the "cow" DNA could be from cross-contamination. A secondary analysis really should be done using a different method. ZooMs is a better method because it works better on degraded DNA. Overall, this all could have been done a lot better. Kurin shouldn't have stated that she was 90% positive it was from the missing boy. Snow should have made it more clear that it was possible that it could be from the kid but more evidence is needed to support this claim. And the DNA could have been done a second time or with better methods.
I will play devil's advocate here. Kurin's osteological analysis was subpar for a forensic investigation. In each of the categories discussed in the "Fast Fact" sheet, she could have given specific examples as to why she determined that it was bone, human, etc. This would have further supported her conclusions. But I'll say she's not a forensic anthropologist, she's a bioarchaeologists. And bioarchaeologists aren't used to doing this type of work. Now to work both sides. These fragments are almost impossible to determine one way or another if no osteological landmarks are evident on the bone. Foramen, ridges, etc. would need to be used to determine the specific bone and that would help determine human or animal. She should not have said that they were human if she wasn't 100% certain. That's what I do. If I'm not sure, then I'll state that the evidence is inconclusive and further laboratory methods would need to be used to determine human or animal (histology, DNA, proteomics, ZooMs, etc.). Rick Snow's report doesn't state if they are human or animal either and he also states that lab methods would need to be used. I would counter his argument that the striations on the largest bone is older than 3 years. Considering this happened in a landslide, this could have impacts on the skeleton that would be consistent with younger than that 3 year marker. The DNA report was also subpar in that they don't definitively state that it is human or animal, they state that it's possible that it is cow. But, as you state, the possible human DNA evident on the bone could be from cross-contamination. But the opposite could also be true that the "cow" DNA could be from cross-contamination. A secondary analysis really should be done using a different method. ZooMs is a better method because it works better on degraded DNA. Overall, this all could have been done a lot better. Kurin shouldn't have stated that she was 90% positive it was from the missing boy. Snow should have made it more clear that it was possible that it could be from the kid but more evidence is needed to support this claim. And the DNA could have been done a second time or with better methods.