The invention relates to systems, devices and methods for the efficient collection, storage, utilization and evaluation of scent samples particularly useful in forensic applications.
Not applicable.
Not applicable.
Since antiquity, the olfactory precision and sensitivity of animals has been known. For almost as long, man has harnessed these capacities for a wide range of applications. Even today, there are no commercial instrumentation systems that can match the sensitivity of pigs trained to detect the subtle aromas of truffles hidden under earth, leaves and brush in the forest. Similarly, dogs trained to track or identify people, or to detect substances such as explosives and marijuana, remain the backbone of law enforcement in an age where instrumentation and computers dominate virtually all other areas of forensics.
Techniques have been substantially advanced from the classic situation where specially trained dogs smell a garment belonging to a runaway criminal, and the chase begins. Dogs have also been used in less frenetic applications, such as the detection of a lost child, and in various forensic comparative applications.
For example, trained dogs may be used to identify suspects in a scent lineup. A garment removed from a crime scene may be permeated with scent sufficient to identify individuals who were present at the crime scene. In such circumstances, detectives may collect garments, home furnishings, or the like and place them in plastic bags to preserve the scents which they carry for a later detection process.
Generally, techniques may be classified as 1) scent detection techniques which involve the provision of a stimulus comprising a scent sample to an animal which is trained to seek and identify another source of the scent, and 2) scent identification techniques involving the presentation of an objective known scent as a primary stimulus to an animal, followed by presentation of a plurality of unknown scents as secondary stimuli to the same animal to determine which of the unknown scents provokes an identification response. This latter procedure it is sometimes referred to as a “scent lineup”.
As alluded to above, recent years have seen the application of electronic instrumentation to scent identification problems. Electronic instrumentation offers the advantage of sensitivity to a wide range of materials including biologicals as well as other substances which may be dispersed by an individual, and/or the things about him, into his environment. Instrumentation outputs, as compared to the binary identity information provided by trained dogs, contain a wealth of information, both quantitative and qualitative. For example, a sample may be screened for a wide variety of materials, the detection of the materials indicated and the quantitative concentrations of such materials included in an output.
Over the years, scent concentration techniques have also been developed. For example, a small area of a gauze pad may be wiped over the entire surface of a hard object, such as a tabletop in an effort to collect scent deposited on the tabletop. The gauze pad is then put in envelope, for example one made of mylar, and the envelope with the gauze pad in it is sealed for later use. Thus, scent may be collected at a crime scene at a point in time when the scents are relatively freshly deposited and most plentiful, and used at a later point in time when scent has been collected from a suspect. In such circumstances, the scent collected from the suspect can be compared to the scent collected at the crime scene to determine whether the scents are the same. Such determination may be made using specially trained dogs.
Techniques are also available for the collection of scent from the air. Thus, if a crime has been detected relatively quickly after the time of its commission, an air pump may be used in a vacuum cleaner-like configuration to drive, for example, all of the air in a room through a collection pad made of gauze. Here again, after the collection process has been completed, the gauze pad, imbued with the scent in the room, is put in a sealed mylar bag for later use. It is noted that in accordance with the invention other means may be used to preserve a collector imbued with odiferous materials, including, in particular, a glass or plastic vial.
While these techniques work well, they do suffer from significant limitations. For example, preservation of a scent in a sealed envelope necessarily involves losses over time. Hence, the desirability of scent collection and concentration, as in the above example of a gauze pad being rubbed over a tabletop, or the alternative example of a vacuum cleaner-like device being used to collect a quantity of scent from the air in a room.
Another advantage of concentration techniques is that the process makes more viable the use of electronic instrumentation, such as a mass spectrograph. In the age of electronic instrumentation, results from such devices often have a greater degree of reliability. Certainly, their operation may be more easily understood and output results more intuitively grasped by a finder of fact in a judicial proceeding. Hence, there is a higher likelihood that a positive indication of identification will be accepted by a jury or a judge in a proceeding.
However, electronic detection systems are substantially less sensitive to odiferous agents as compared to animals. Accordingly, any system or method which results in concentrating a greater amount of scent improves the possibility of using electronic instrumentation. Likewise, such techniques improve the shelf life of scent samples in a scent bank. Finally, concentration of scents in a sample by more efficient collection also improves the possibility of a positive indication in a wider variety of circumstances, when using animals such as dogs to perform a scent detection or identification operation.
In accordance with the invention a scent collection method comprises putting an item bearing a sample of a scent to be identified in an enclosure and heating the item. A quantity of air is introduced into the enclosure. The air from the enclosure is withdrawn after the item has been optionally heated. The withdrawn air is passed through a scent collection member to collect scent on the scent collection member. The scent collection member is cooled during the scent collection process and the scent collection member is then sealed in an envelope. The scent collection member is removed from the envelope in which the scent collection member has been sealed. The scent collection member is then heated and air passed through the scent collection member. The air passed through the scent collection member is used as a stimulus or other input in a scent identification procedure.
The procedure may comprise using electronic instrumentation or trained animals to obtain information respecting the collected scent. Heating of the item may be performed after the enclosure has been sealed, after an item of information has been uncovered relating to the sample.
An alternative method of collecting scent from a smooth surface for forensic evaluation, comprises wiping a scent collecting member over a portion of the smooth surface and enclosing the smooth surface in a scent-containing container containing air. The smooth surface is optionally heated with a sufficient degree of heat to release relatively volatile scent material into the air, while retaining less volatile material on the smooth surface. The air is driven through a collection member to collect in the collection member volatile scent material released into the air. The collection member may be cooled while driving the air through the collection member to collect in the collection member volatile scent material released into the air.
In accordance with the invention a scent collection apparatus comprises an enclosure for receiving an item bearing a sample of a scent to be identified, a first heater for increasing the temperature of the item, and an air blower having an output and having an input, the input being coupled to withdrawn air from the enclosure containing the item. A scent collection member is coupled to receive the output of the air blower, whereby odiferous materials entrained within the air output by the blower are caused to accumulate on the scent collection member. A cooling member may be thermally coupled to the scent collection member. A second heater may be coupled to the scent collection member. A second air blower may be coupled to drive air to the scent collection member. A conduit passes air passed through the scent collection member to an output port for use as a stimulus in a scent identification procedure. The scent collection member may comprise a zeolite, or activated charcoal.
The cooling member may comprise a Peltier cell. The first heater may comprise an electrochemical heat releasing cartridge. Alternatively, the cooling member comprises an electrochemical cooling cartridge. The second heater may comprise an electrical heater. The cooling member may also comprise a refrigerant based cooler.
In accordance the invention, it is also possible to collect scent from a sample using a vacuum, with or without the heating of the sample or cooling of the collector. The invention also provides for the output of scent from a collector using a vacuum with or without the heating of the collector.
The operation of the invention will become apparent from the following description taken in conjunction with the drawings, in which:
FIGS. 5 is a cross-sectional view similar to that of
FIGS. 6 is a perspective view of a slotted bottle for cooling or heating the scent collection member constructed in accordance with the present invention;
In accordance with the present invention, a collection cartridge 10 constructed of a tubular plastic member 12 is provided with an internal collection member 14 which may be made from a wide range of materials, such as packed fibrous material, for example cotton or polyester. In accordance with a preferred embodiment of the present invention, the material may be selected with desired surface characteristics. For example one may use a hydrophobic material or a hydrophilic material, depending upon the characteristics of the materials which one anticipates collecting.
In accordance with a preferred embodiment, collection member 14 is made of charcoal. Charcoal or acticated charcoal is particularly advantageous, as it is porous and the pores can absorb and retain large amounts of molecules. Collection member is baked and out gassed to ensure that the charcoal is free of any contaminating scents from handling, manufacturing, and so forth. The uncontaminated collection member is then packaged in a sealed bag, made, for example, of metalized plastic film, such as Mylar (R) plastic. The bag is opened just before it is to be used. This is especially critical in the event that crime scene air is to be used as a scent source.
Collection member 14 may also be of a non-fibrous nature, such as open cell foam plastic, particles, or any other material whose structure allows air to pass through it, such as a collection screen, wire mesh, or the like. All of the same may also be given desired hydrophilic or hydrophobic characteristics.
In accordance with one particularly preferred embodiment of the invention in which a collection cartridge 10 is cooled in order to maximize the amount of scent material collected, collection members 14, having a high specific heat or thermal capacity and thus the ability to absorb or release a large amount of heat, if cooled prior to a collection operation are particularly effective to collect material for analysis.
Sand, metal grindings, powdered glass and the like will also function, if pre-cooled, to effectively condense odiferous materials.
Charcoal and zeolites and other porous structures are particularly preferred collection materials in collection member 14.
If desired, the collection member 14 may be kept in place by a pair of support walls 16 and 18. Support walls 16 and 18 define holes 20, which provide for the passage of air containing odiferous materials. During use, air carrying various scents is caused to enter into an inlet port 22, pass through holes 20, and enter collection member 14. The odiferous materials are then caused to collect on the constituent fibers, particles, or the like of collection member 14. Air which has been stripped of odiferous materials then passes through holes 20 in support wall 16 and pass to output port 24.
When the collection operation has been completed, airtight plugs 26 and 28 may be inserted into ports 22 and 24 to lock in collected odiferous material. In accordance with a preferred embodiment of the invention, this sealing operation would be made further effective by putting the plugged collector 10 in a plastic bag (for example a metalized plastic bag), and then sealing the bag and removing all excess air from the bag.
An alternative collection cartridge 110 is illustrated in
Such cooling may be achieved using something as simple as a bag of ice water, dry ice, or the like. Alternatively, referring to
An apparatus 350 for collecting odiferous material in accordance with the invention is illustrated in schematic form in
An alternative arrangement is illustrated in
Referring to
Referring to
The methodology of the present invention is illustrated in
An alternative process is illustrated in
In many cases, and odors is taken from a crime scene and have information which one would like to preserve until more evidence is found. The options are to create an electronic record on the scent and put it into a database for later identification as in the methods of the
In accordance with this method 900, an item of evidence is encased at step 910, treated as in the method of
The collector cartridge containing the later discovered evidence is then heated, and heated air is blown through it for analysis at step 1030. Likewise, the stored sample is selected at step 924, heated and subjected to a flow of heated air and the exhaust collected and analyzed at step 930, in much the same manner as the method of
If desired, multiple samples may be taken at a crime scene, or even from a single garment by cutting the garment into two or more pieces, and when an identification is made with a forensic instrument, dogs may be used to make a collaborating identification.
Referring to
In accordance with the invention, it is not necessary that such a charcoal filter, or any filter be cooled. Likewise, it is not necessary that samples of material bearing scents, such as clothing, be heated.
It is also noted that accordance with the present invention a collection cartridge, for example any charcoal or zeolite collection filter may be simply left in a room where a crime has been committed and scents allowed to be absorbed into it. Another option in accordance with the present invention is to blow air from the crime scene through a collector. For example, the room where the crime has been committed may be sealed and a scent collection cartridge placed in the room with a blower to blow air through it.
It is particularly advantageous in accordance with the present invention to use scent collection materials, such as charcoal or zeolites which have pores in them and which have the capacity of collecting large amounts of scent.
It is also noted that in accordance with the present invention, specific scent-collection materials, such as charcoal or zeolites may be selected for their characteristic of being selective or effective with respect to the collection of various target scent material(s).
In addition, it is noted that any appropriate a device may be used for the purpose of measuring the characteristics of odiferous materials, as may be used in the art. However, it is believed that a GC head space mass spectroscopy instrument is most effective in quantitatively measuring a “scent fingerprint” given the relatively modest amounts of odiferous material typically found or collectible at a crime scene.
While an illustrative embodiment of the invention has been described, it is, of course, understood that various modifications may be made by those of ordinary skill in the art. Such modifications are within the spirit and scope of the invention, which is limited and defined only by the appended claims.