California Association of Criminalists
Since 1954
TEMPERATURE AND HUMIDITY EFFECTS ON FINGERPRINTS
Peter Barnett, Richard Berger
The determination of the age of a latent fingerprint is frequently important. Little, if any, systematic study of the effects of varying environmental conditions on the permanency of latent fingerprints is reported in the literature. Much of the opinion expressed in standard texts review articles, and by experts appears to be anecdoted and unsubstantiated by controlled studies. In this study a substantial number of fingerprints from 12 individuals were stored under 5 different environmental conditions. At intervals of 24 and 72 hours, 1, 3, 5, and 7 weeks, samples of the latent prints from each environment were developed by dusting. These prints were then graded on an arbitrary scale for clarity of ridge detail. These scores were then compared to determine the effect of the varying environmental conditions over a period of time.
A NEW PRESUMPTIVE BLOOD TESTING REAGENT
Marty Blake
The carcinogenicity of benzidine has recently resulted in proscribed usage of the reagent for presumptive blood testing purposes. A new presumptive blood reagent, tetramethylbenzidine, has been synthesized by Aldrich Chemical Company. Studies thus far indicate the compound to be noncarcinogenic. Tetramethylbenzidine will be compared with the conventional reagent benzidine, orthotolidine, leuco-malachite green and phenolphthalein.
CROSS EXAMINING THE DEFENSE EXPERT IN CASES INVOLVING THE POLYTYPIC NATURE OF CANNIBIS
Paul T. Zeionis, Robert D. Robertson
During the past months, considerable controversy has arisen in regard to the polytypic or monotypic nature of Cannabis. In many cases the counsel for the defense have relied on the testimony of an opposition expert, usually a plant taxonomist, to challenge the Government's establishment "beyond a reasonable doubt" of the presence of Cannabis sativa L. When such an expert is encountered it is often necessary for the forensic chemist to aid the prosecutor in his cross examination of the opposition witness and in his preparation of a rebuttal.
GUNSHOT RESIDUE ANALYSIS WITH A NEW GRAPHITE FURNACE
David H. Elgas, Eric St. John
A technique is described employing a new ultra high temperature graphite tube furnace for flameless atomic absorption analysis of barium and antimony in gunshot residues. A comparison is made between samples taken with cotton swabs wetted with 5% HNO3 and a rapid tape lift method. Residue levels from various caliber weapons are compared and the use of the face as a sample control is suggested. Bloodstained samples are analyzed after pre-ashing in a microboat on a hot plate. The sensitivities for barium and antimony are 7 x 10-12g and 13 x 10-12g respectively.
ENERGY DISPERSIVE X-RAY: CRIMINALISTICS USE AND POTENTIAL
Fred Tulleners
The presentation will include the basics of energy dispersive x-ray, how it works, what it can do, and some of the pitfalls encountered in data interpretation and how it is currently being used in the Department of Justice Laboratory. The second part will focus on a program by the California Department of Justice to use these instruments as a vehicle for data exchange, and data retrieval. Essentially, we are looking at the feasibility of encoding standard samples on magnetic tape and using the tape as a library source for the comparison and identification of unknown samples. Currently, we are looking at the reproducibility of interchange and the types of encoding methods.
ALTERNATIVE QUICK, INEXPENSIVE TECHNIQUES FOR THE ANALYSIS OF BLOOD STAINS - ERYTHROCYTIC ACID PHOSPHATASE, ESTERASE-D, PHOSPHOGLUCOMUTASE, AND HAPTOGLOBIN
James J. Streeter, Duane I. Lovaas
Alternative methods for determining Erythrocyte Acid Phosphatase, Esterase-D, and Phosphoglucomutase in bloodstains are described. The supporting medium for electrophoresis is hydrolyzed starch. Advantages discussed are an increased sensitivity and a shorter electrophoresis time. The alternative method described for determining Haptoglobin in bloodstains uses density gradient acrylamide gels. The gels are prepared using gradient and gel forming tanks constructed inexpensively in the laboratory. Subsequent horizontal electrophoresis eliminates the expensive vertical tank formerly used.
COMPARISON OF CANNELURE DIE MARKS
J. Robert Davidson
Cannelures of bullets are produced by rolling the bullet under pressure against a multi-toothed hardened steel die. By comparing the die impressions on questioned and known bullets, it is possible to specifically identify bullets as having been made by the same machine and therefore the same manufacturer. Under favorable circumstances, it may be possible to identify bullets as being from a particular manufacturing lot. This type of comparison as furnished circumstantial evidence in three homicide investigations in which the gun was not recovered or not identifiable and in which ammunition was recovered from the suspect.
Before drawing any conclusions as to the significance of the identification of bullets being made on the same machine the examiner should determine from the manufacturer as much information as possible about the manufacturing history and distribution of the particular bullet lot. When possible, authenticated bullet samples from different periods of time in the manufacture of a particular sample should be obtained and compared, as well as other bullet lots manufactured on the same machine before and after the questioned bullets. A study is in progress to determine the degree of change of the individualizing characteristics of a particular cannelure die over a period of time of use.
REPORT ON THE 7TH IAFS MEETING, ZURICH, SWITZERLAND
John D. DeHaan
A short summary of some of the more interesting presentations at the Seventh International Meeting of Forensic Sciences will be presented.
INORGANIC ANALYSIS OF 1974 U.S. AUTOMOTIVE TOP COATS
Thomas Keener, Victor Reeve
This presentation deals with the elemental qualitative and semiquantitative analysis of 1974 U.S. automotive paints, utilizing a Finnigan Model 900F Energy Dispersive X-Ray Spectrometer. This EDX analytical system incorporates a mini-computer to receive, store, and present data. The aforementioned paint samples were received from the National Bureau of Standards' (NBS) Law Enforcement Standards Laboratory as a collection, representative of the paint types used on all U.S.manufactured automobiles in 1974. Aspects to be discussed in this presentation include EDX system stability, homogeneity and variance of similarly catalogued samples from different NBS collections, categorization of paints by base constituents, and comparison of data with respect to similar appearing paint standards.
This study represents an important application to forensic science in identifying and comparing suspect paints. The analytical system provides for the analysis of a variety of materials in a large range of sample sizes and concentrations, nondestructively. Slide presentations illustrating the EDX system, spectral displays of paints pertaining to this discussion, and graphs used in data comparison of paints will be displayed.
SPERM DIAPHORASE: GENETIC POLYMORPHISM OF A SPERM SPECIFIC ENZYME
Kevin Caldwell, Edward Blake, Dr. George F. Sensabaugh
Human sperm contains an enzyme with diaphorase activity that appears to be unique to sperm. Electrophoretic analysis of the diaphorase activity in sperm of different individuals reveals three phenotypic patterns. This polymorphism can be explained in terms of two alleles segregating at an autosomal locus; the allele frequencies have been determined to be 0.67 and 0.33. This is the first reported example of a sperm specific genetic polymorphism in humans; it should be a useful marker for genotyping semen.
WHAT HAPPENS WHEN BLOOD DRIES: THE PERSISTENCE, STABILITY AND PRESERVATION OF PROTEINS IN BLOOD?
Dr. George Sensabaugh
When blood dries or is stored for long period of time, various changes occur. These changes include generalized loss of solubility, development of polydispersity in electrophoretic mobility (storage bands), and loss of enzyme activity. Upon occasion, the changes can result in the mistyping of genetic markers, e.g. EAP B types can begin to look like CB types, AK 2-1 types can begin to look like 1 type. The chemical processes responsible for these changes can be postulated; they include microbial action, modification by enzymes present in blood, free radical reactions, and reactions with components in blood and dehydration condensations. These processes are dependent upon light, temperature, and water activity. Preliminary experiments indicate that covalent crosslinking of proteins occurs more rapidly at low and high water activities then at intermediate water activities. Further studies on the nature of these processes will be required before optimal conditions for dried blood storage can be developed. In the mean time, storage at low temperatures will retard changes. The addition of glycerol to stored samples may have some preservative effects.
ASSESSMENT OF BLOOD INDIVIDUALITY
G. G. Sensabaugh and C.V. Morton
Three questions were considered:
The first question was answered by showing the evidence for genetic variation in alpha Fucosidase. (Turner, et.al. Amer J. Human Genet. 27:651, 1975). The value of this polymorphism for distinguishing between individuals can be measured in terms of an identity index: the probability that two individuals selected at random from the population will be identical with respect to phenotype. Identity indices between populations can show the value of a genetic polymorphism for distinguishing individuals from different populations. Finally, the question of "rareness" and "commonness" was discussed in terms of a population typed for 17 genetic markers. When this many typing systems are used, all individual phenotypes are rare, although some are more rare than others. This demonstrates that "rareness" and "commonness" must be considered both in the absolute sense and in the context of expectation.
CHEMISTRY OF ANTIGENIC DETERMINANTS
Francis A. Fitzpatrick, Orange County Sheriff-Coroner; George Sensabaugh, University of California
THE RE-EXAMINATION OF THE RFK BULLETS
C. Morton, The Institute of Forensic Science
Re-examination of firearms evidence in the RFK assassination. A synopsis of the evi-dence examined and the results of the seven member panel, which refuted the second gun theory, were presented. The problems associated with attempts to compare test and evidence bullets, as well as the inter-comparison of evidence bullets, were also discussed.
