Court Filing
EXHIBIT S-10 Amended Supplemental Expert Disclosure: Tina Walthall The State has previously disclosed Tina Walthall, Forensic Scientist III, as an expert witness in the field of forensic science, which includes, but in no way is limited to, latent prints. The State hereby incorporates its previous response and attachments filed on December 18, 2024, and is hereby supplementing its response as follows. Walthall may explain what friction ridge skin is, what latent prints are, what exemplars are, consumption of evidence with regards to latent print processing, how items are processed for latent prints in the laboratory, how recovered prints are preserved in the laboratory, factors affecting the recovery of latent prints, how latent prints are utilized for comparison to include verification and confliction resolution processes, and the use of the Multi-Modal Biometric Identification System (MBIS). Walthall is expected to testify about her involvement in this case in which she processed item 1 (Ka-Bar leather knife sheath with USMC logo) for latent prints. Walthall did not observe or develop and latent prints from item 1. Walthall's explanation of this can be found in Walthall's Report 2 (Bates Pages 267-268). Walthall processed other items (66, 68, and 69) for latent prints in this case as well. The report for these items can be found in Walthall's Lab Report 15 (Bates Pages 988-989). Walthall will testify friction ridge skin is a specialized type of skin on the hands and feet that is capable of being used to establish or confirm identity. This skin consists of ridges and valleys located on the gripping surfaces of the hand and feet that form patterns. Fingerprints are classified into the following pattern types: arches, loops, and whorls. Individual ridges have features or characteristics (minutiae) that are highly discriminating EXHIBIT S-10 STATE'S EXHIBIT Amended Supplemental Expert Disclosure: Tina Walthall exhibitsticker.com (Sealed) 1 S-10 CR01-24-31665 between individuals. These features are formed prior to birth and remain relatively unchanged throughout one's life barring trauma or disease. Friction Ridge detail refers to the features and characteristics present in friction ridge impressions. This detail may be described as level 1 (direction of ridge flow), level 2 (ridge path), level 3 (ridge shape and pore location). Friction ridge details permit comparison and subsequent identification of fingerprints. Latent prints are impressions of friction ridge skin patterns that can be left on a surface when contact is made. The term “ latent ” refers to prints that are not visible prior to utilizing a development method; latent prints are often made up of various matrices, including sweat and oils that are colorless and require development with chemicals or powders to be seen. Prints at a crime scene may also be made from other materials that may coat the skin, like blood or dirt. Although latent means hidden, any prints recovered from a crime scene or from items of evidence are often referred to as latent prints. Exemplars are intentional recordings of the friction ridge skin of an individual. These may be collected with black ink, powder / adhesive, electronic imaging, and / or other capture methods. These known exemplars can then be used for comparison against latent print evidence. Exemplars may include any / all areas of friction ridge skin from the hands or feet of an individual. Types of exemplars include fingerprints, palm prints, major case prints (tips, joints, sides of fingers), and footprints. Items are often submitted to the laboratory for multiple types of analysis. Surfaces that require other forensic examinations (trace, biology, etc.) are evaluated to determine if latent print processing techniques will have an impact. Examiners routinely consult with scientists from other disciplines to ensure all potential evidence is considered for EXHIBIT S-10 Amended Supplemental Expert Disclosure: Tina Walthall (Sealed) 2 preservation. Once an item is processed for latent prints, reprocessing will generally not be successful, so it is imperative that processing techniques are completed in the proper sequence. An examiner in the laboratory uses chemical, physical, and light techniques to attempt to recover latent prints from a variety of surfaces. The techniques selected (visual, alternate light source, cyanoacrylate, dye-stain, powder, ninhydrin, etc.) are generally based on the type of surface (porous, semi-porous, or non-porous), but may also take into consideration what it is believed that the latent prints may be made of (sweat, oil, blood, etc.). Techniques are generally performed in a sequential manner from the least destructive to most. Observed or developed latent prints can be preserved by digital photography, scanning, and lifting techniques. There are many variables that affect whether a latent print is left and able to be recovered. These variables include conditions existing before, during, and after the time the person touched or handled the surface. Pre-transfer conditions include individual subject factors (latent print's composition and a person's ability to leave latent prints). These factors differ from individual to individual and may even vary within the same individual. Factors also include deposition / transfer factors such as the surface (material, condition, texture, etc.) and how the item was handled (length of contact, pressure, area of contact, contaminants, smearing during contact etc.). Post Transfer Conditions / Environmental factors include the conditions that the latent was subjected to after it was deposited (additional handling, packaging, environmental exposure, etc.). Latent print comparison refers to the process of analyzing latent prints and comparing them to known exemplars in attempt to determine their source. Examiners EXHIBIT S-10 Amended Supplemental Expert Disclosure: Tina Walthall (Sealed) 3 utilize the ACE-V methodology which is a specialized version of hypothesis testing. ACE- V stands for analysis, comparison, evaluation and verification. Analysis is the assessment and documentation of friction ridge impressions to determine suitability for comparison. This assessment includes consideration of the quality and quantity of detail, orientation, anatomical source (finger, palm, etc.), type of matrix, deposition factors, complexity, substrate considerations, environmental factors, development mediums, and preservation methods. Latent prints may be of value for comparison or may be deemed to contain insufficient detail for comparison purposes. Impressions deemed " of value " are impressions that in the opinion of the examiner, contain sufficient quantity, quality, and specificity of ridge detail to warrant a comparison. Examiners also take into consideration how discriminating the location and arrangement of features within an impression are. When quantity is low, quality must be relatively high. Whereas when quality is low, quantity must be relatively high. It is not uncommon for latent print examiners to have conflicting opinions with regards to sufficiency. Latent prints are also evaluated for their suitability for database entry (AFIS, ABIS, MBIS, etc.) Comparison is the side-by-side, back and forth, examination of friction ridge detail between a latent print and a known print to determine whether the detail is in agreement or disagreement based upon features, sequences, and spatial relationships within the tolerance of clarity and distortion. Generally, latent prints are first compared against various known prints belonging to subjects associated with the evidence (victims, witnesses, and / or suspects if known). In the event that the latent prints are not identified or that there are no known prints available with which to compare, the prints may be entered into a computer database (MBIS) and compared to a large group of persons who have prints on file. EXHIBIT S-10 Amended Supplemental Expert Disclosure: Tina Walthall (Sealed) 4 Evaluation is the formulation of a conclusion based upon analysis and comparison of friction ridge impressions. Conclusions that may be reached are source identification, source exclusion or inconclusive. Source identification is the examiner's opinion that two impressions originated from the same source. The observed features are in sufficient correspondence such that the examiner would not expect to see this level of agreement in impressions that came from different sources. Nor did the examiner find features in disagreement that would lead them to conclude that the impressions are from different sources. There is no scientific basis for a predetermined number of corresponding friction ridge details be present in two impressions in order to effect a source identification. Source exclusion is an examiner's conclusion that two impressions did not originate from the same source. The observed features are in disagreement such that the examiner would not expect them to have originated from the same source. Inconclusive is an examiner's inability to reach a conclusion of source identification or exclusion. Inconclusive may be due to lack of quantity or quality of detail in the latent or known impression. Verification is the independent examination by another qualified analyst using the ACE methodology to either support or refute the conclusions of the original examiner. ISPFS requires verification of all conclusions rendered in a case (value determinations, identifications, exclusions and inconclusives). Routine verification is considered “ open ”. This means the verifier conducts independent analysis but has access to the original analyst's notes and images. Blind verification, in which the verifier has no knowledge of or access to the original analyst's conclusion, may be performed in cases of single identifications generated from a database, as a means of conflict resolution, or as an additional quality measure for complex impressions. EXHIBIT S-10 Amended Supplemental Expert Disclosure: Tina Walthall (Sealed) 5 The decision made at the evaluation step is an examiner's opinion based on their personal observations. These observations may be influenced by training, experience, risk tolerance, bias and many other factors. Once this decision is made, the case is sent to another qualified analyst for verification. It is not uncommon for analysts to have different opinions and come to differing conclusions during the ACE-V process. ISPFS has a conflict resolution policy for navigating and documenting such instances. Analysts are encouraged to resolve differing opinions by re-examination and / or discussion to arrive at a mutually agreed upon conclusion that is supported by the observed data. When this cannot be achieved, a blind verification by an additional analyst may be conducted. If blind verification does not result in a resolution, a consensus opinion or administrative opinion may be sought. The Multi-Modal Biometric Identification System (MBIS) is the general term referring to any system that contains a database of ten-print, latent prints and palm prints. MBIS also includes software that is utilized to search available databases. Idaho is a member of the Western Identification Network and is able to search the databases of WIN central site members and the FBI. MBIS allows for searching latent prints against known fingerprint and palm print database records. The system can also be used to search latent prints against other latent prints. EXHIBIT S-10 Amended Supplemental Expert Disclosure: Tina Walthall (Sealed) 6