Here's a breakdown of the situation:
* How Lip Prints are Used: Lip prints, like fingerprints, are considered unique to an individual. Examiners compare lip prints found at a crime scene to those taken from a suspect. Characteristics like the patterns of lines and grooves on the lips are analyzed.
* Admissibility Challenges:
* Lack of Standardization: Unlike fingerprint analysis, there is no universally accepted standard methodology for collecting, classifying, and comparing lip prints.
* Subjectivity: The interpretation of lip print patterns can be subjective, leading to potential bias.
* Limited Research: There is less scientific research supporting the uniqueness and permanence of lip prints compared to fingerprints.
* Daubert Standard/Frye Standard: In many jurisdictions, evidence must meet certain standards to be admissible in court (like the Daubert Standard in federal courts in the US, or the Frye Standard in some state courts). These standards assess the scientific validity and reliability of the evidence. Lip print analysis often struggles to meet these standards due to the issues mentioned above.
* Court Decisions:
* Some courts have admitted lip print evidence, particularly when it is used to corroborate other evidence.
* Other courts have rejected lip print evidence, citing concerns about its reliability and the lack of scientific validation.
* The admissibility often depends on the specific circumstances of the case, the qualifications of the expert witness, and the jurisdiction's evidentiary rules.
* Use in Conjunction with Other Evidence: Lip print evidence is generally more persuasive when it is presented alongside other, more reliable forms of evidence, such as DNA, fingerprints, or eyewitness testimony.
In summary, while lip prints have been used in court, their admissibility is not guaranteed and is subject to significant scrutiny. Their reliability as a sole source of identification is questionable, and they are generally considered less reliable than other forensic methods like DNA analysis or fingerprinting.