Personal Attention.
Aggressive Defense.

Photo of Thomas C. Mooney

Is bite mark analysis unreliable?

On Behalf of | Nov 7, 2022 | Criminal Defense

A new report released by the National Institute of Standards and Technology provides a revealing condemnation regarding the validity of bite mark analysis in criminal cases. Taking a second look has uncovered potential unreliability and a lack of scientific support.

Instead of being an objective way of testing, bite marks may be more subjective when it comes to matching a suspect’s teeth with marks left by teeth. Research reveals that the impressions fail to leave reliable patterns, making identification difficult, if not impossible. Even more alarming is the lack of overall standards and fails vital scientific testing

The NIST report focuses on multiple assumptions surrounding bite mark analysis, all of which purportedly are not supported by data.

Significant shortcomings in identification

Teeth patterns found after a bite are not unique to one person, seemingly removing any comparisons to DNA or fingerprint analysis. The act of biting into someone’s skin fails to leave reliable evidence. The angle of the mouth may differ due to movement during the purported attack, not to mention the skin’s elasticity.

Anything resembling a “gold standard” remains elusive in this unreliable process.

For experts and researchers, this is not a new issue. For decades that go back to the 1960s, they have pleaded for more rigorous research to make identifications more reliable.

A 2019 workshop on human bite marks found it highly unlikely that teeth had the characteristics necessary to clearly identify a perpetrator. Simply put, human teeth do not provide that much detail to single it out to one potential suspect.

Inter-industry disputes

Even bite mark analysts are at odds over what bite mark evidence shows. A 2015 study requested that 39 experts review 100 case photos to determine if a bite mark came from a human or something else. In eight percent of the cases, ninety percent of experts were in agreement. Simply put, nearly every case saw different findings by individual experts.

More in-depth research is needed to avoid wrongful convictions and potential rights violations of criminal suspects.