Physical evidence types

Forensic Serology. Blood, often associated with crimes of violence, is powerfiil physical evidence. Its presence suggests association with the criminal act and blood can be used to associate suspects and locations with the bleeder. Blood is a complex mixture of cellular material, proteins, and enzymes and several tests are available for suspected bloody evidence. A typical test protocol involves (/) determining whether blood is present, (2) determining if it is human blood, (J) typing the blood, and (4) when appHcable, performing DNA typing. 

Examination of physical evidence provides two subtle and different types of conclusion. All members of a class or group have identical characteristics. Types of physical evidence which exhibit class characteristics are paint, glass, fibers, fabric, building material, etc. This type of physical evidence is said to be identified. The best that chemical and physical examinations can ever do is to place items into groups of similarly manufactured ilems. It is not possible to differentiate one item of evidence as being uniquely distinguishable from another. 

Measures of performance. In the fall of 1973, three crime laboratories (Contra Costa County, California Dade County, Florida and Columbus, Ohio) were selected as representative sites for the development of measures of performance and effectiveness. The Planning Research Corporation, with Mr. Lowell W. Bradford as Project Director, was awarded the task of developing a conceptual criminalistics laboratory model and methods for measuring the performance of such laboratories. Teams of researchers each spent two months collecting data on the operations of the three previously mentioned laboratories. Data were gathered on the forms of physical evidence submitted and the types of crimes from which the evidence had been recovered. Evidence and cases were traced through the laboratories as examinations were performed and results were formulated. 

The larger number of points of identification that are determined, the more certain becomes the conclusion regarding the identification of questioned inks. Such forensic scientific philosophy is true not only of ink comparison but of other types of physical evidence such as soil, paint, hair, bullets and fingerprints. ... 

There are three major subdivisions of the process of physical evidence evaluation—collection, laboratory evaluation, and court presentation of results and their significance. How should personnel be trained for each of these functions It need hardly be pointed out that the crime investigator should be well aware of which types of evidence are useful for investigative purposes, what evidence the local, regional, or federal... 

Abstract Planet formation is a very complex process through which initially submicron-sized dust grains evolve into rocky, icy, and giant planets. The physical growth is accompanied by chemical, isotopic, and thermal evolution of the disk material, processes important to understanding how the initial conditions determine the properties of the forming planetary systems. Here we review the principal stages of planet formation and briefly introduce key concepts and evidence types available to constrain these. 

The bulk of the physical evidence for cross-links depends on the existence of a complete lattice formed by intermolecular cross-links. The separation of components of denatured collagen sheds light on both types of linkage. 

The centers described above represent most of the types which have been characterized in irradiated silica gel by noncatalytic and non-chemisorptive experiments. Each of the types described may well consist of a range of centers differing by the variation of some parameter like distance or neighborhood composition. There are undoubtedly other types for which physical evidence has not yet been noticed and others which will prove to have no useful physical markers. 

The need for the identification of textile fibers in forensic science is a common one. Many types of crimes, when investigated, yield fibers as physical evidence. Crimes in which fibers may be deposited at the scene include robbery, breaking and entering, homicide, rape, assault, and hit-and-run accidents involving a victim. 

The skeletal structure of oxindoles of the secoyohimbane type, typified by rhynchophylline and isorhynchophylline, rests on a mass of chemical and physical evidence which has been discussed in earlier volumes. Some physical properties of members of this group are presented in Table II. The UV spectra of all the oxindole alkaloids are closely related (Table III) and are satisfactorily explained on the basis of contributions of an oxindole and a -methoxy acrylic ester... 

List three types of physical evidence that indicate a chemical reaction has occurred. 

Aunt and nephew conferred by telephone further over the weekend to prepare not one but two papers for Nature, a joint explanation of the reaction and Frisch s report of the confirming evidence of his experiment. Both reports— Disintegration of uranium by neutrons a new type of nuclear reaction and Physical evidence for the division of heavy nuclei under neutron bombardment —used the new term fission. Frisch finished the two papers on Monday evening, January 16, and posted them airmail to London the next morning. Since he and Bohr had already discussed the theoretical paper and since the experiment only confirmed the Hahn-Strassmann discovery, he did not hurry to let Bohr know. 

There are many types of physical evidence present at fire scenes. In general, the physical evidence can be divided into four categories ... 

In theory, all four types of physical evidence can be found at a fire scene. In practice, however, much or all of the physical evidence may be destroyed by the fire itself or by the efforts to suppress the fire. 

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