GB2364932A

GB2364932A - Filter unit for collecting DNA evidence

Info

Publication number: GB2364932A
Application number: GB0017671A
Authority: GB
Inventors: Peter Anthony Crouch; Christopher Huw Braham
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-07-20
Filing date: 2000-07-20
Publication date: 2002-02-13
Anticipated expiration: 2020-07-20
Also published as: GB2364932B; WO2002008726A3; WO2002008726A2; AU2001272644A1; GB0017671D0; US20020170916A1

Abstract

A filter unit is placed in the drain outlet from a shower, bath or wash basin and used to collect DNA evidence from a victim or suspected perpetrator of a crime. The filter unit comprises a housing 10 with a strainer member 14 closing its lower end. The strainer member is a mesh with openings 16 of a size to trap human cells, hairs and fibres from clothing. The openings 16 may be larger adjacent the periphery. A lid 24 with handle 28 is screw threaded or snap fitted to the housing 10, which may be made of rubber. The lid may act as a plug during bathing, and be removed to allow the water to drain away through the strainer member. The strainer member 14 may have ribs over its surface to assist in the collection of evidence and/or a collection chamber for larger items may be provided radially outwardly of the strainer member. Further evidence may be collected by wiping the bath with a cloth wipe.

Description

2364932 EVIDENCE COLLECTION DEVICE AND METHOD This invention relates to a

device for use in the collection of evidence, and also to a method of collecting evidence, making use of the evidence collection device.

It is common after an attack, for example rape, has occurred for evidence to be collection from the victim of the attack. The evidence, typically in the form of biological materials which contain the DNA of the attacker, or fibres io from the attackers clothing, is collected using a number of techniques, for example by removing materials from beneath a victims finger nails and by taking swabs from the victim. Although such techniques result in the successful collection of evidence, there is always the risk that some evidence which could be used to identify the attacker is missed, and as a result of the failure to collect such evidence, there is a risk that the attacker may not be caught or insufficient evidence to conclusively identify the attacker is collected.

It is an object of the invention to provide an evidence collection device and a method of collecting evidence which can be used to reduce the risk of evidence failing to be collected.

According to a first aspect of the invention there is provided an evidence collection device comprising a housing having a closable lid, at least part of the housing being defined by a strainer member adapted to allow water entering the housing to escape therefrom through the strainer member, but to collect and retain within the housing, particulate matter carried by the water.

2 The strainer member includes a plurality of openings, the openings preferably being sufficiently small to ensure that human cells are retained within the housing. The openings of the strainer member may be of a uniform size. Alternatively, the openings may be of non-uniform size, for example the openings in a central part of the strainer member being of smaller dimensions than those located towards the edges of the strainer member. Such an arrangement may be advantageous in that the larger openings allow water to escape from the housing at a relatively fast rate. A vortex formed as a result of the water passing through the housing tends to separate relatively large io particulate matter from smaller matter, the smaller matter tending to collect in the central part of the housing, where the openings in the strainer member are smaller, larger matter tending to collect at radially outer parts of the housing where the openings are larger, thus the provision of the larger openings need not significantly increase the risk of matter escaping from the housing.

The housing is conveniently of dimensions to allow it to be received within and close the outlet of a bath, shower or wash basin.

The lid of the housing is conveniently securable in position on the remainder of the housing by screw threads. It will be appreciated, however, that other techniques could be used to secure the lid in position, for example the lid may be snap-fitted to the remainder of the housing, and may be held captive to the housing, if desired, by a flexible strap.

According to another aspect of the invention there is provided a method of collecting evidence comprising locating an evidence collection device of the type defined hereinbefore within the outlet of a bath, shower or wash basin, allowing the individual from whom evidence is to be collected to bath, shower or wash, allowing water to escape from the bath, shower or basin, the 3 water entering the housing and passing through the strainer member, particulate matter carried into the housing being unable to pass through the strainer member and being retained within the housing, and closing the lid to trap the collected matter within the housing.

It will be appreciated that, where used in a shower, a step of opening the lid may be performed prior to commencement of showering, whereas when used in a bath or basin, the lid may be kept in a closed condition until after completion of the bath/wash, and then removed to allow the water to drain io from the bath/basin.

A subsequent operation of wiping the bath, shower or basin using a cloth or wipe having a known DNA content may be performed to collect any matter adhering thereto.

The invention will flirther be described, by way of example, with reference to the accompanying drawing which is a diagrammatic cross sectional view of an evidence collection device in accordance with an embodiment of the invention.

The attached drawing illustrates an evidence collection device which comprises a generally cylindrical housing 10 of short axial extent, the housing 10 being of diameter chosen to allow the housing 10 to be received with the outlet of a bath. The housing 10 is of open, tubular form, and is conveniently manufactured from a rubber or synthetic rubber- like material dimensioned such that, when received within the outlet of a bath, the housing 10 forms a substantially fluid fight seal within the outlet.

4 The lower end 12 of the housing 10 is closed by a strainer member 14. The strainer member 14, in a simple embodiment of the invention, takes the form of a mesh material having openings 16 therein of dimensions sufficiently small that, although water can pass through the openings 16 of the mesh material, particulate matter carried by the water, for example human cells, hairs, fibres from clothing etc, cannot pass through the openings 16.

The upper part 18 of the housing 10 is provided with internal screw thread formations cooperable with external screw thread formations provided on a io lid member 24. The lid member 24 is of generally circular shape, arranged to be received within the upper part 18 of the housing 10. When secured in position, the housing 10, lid member 24 and strainer member 14 together define a closed volume 26. As shown, to assist in securing the lid member 24 in position, a handle 28 is formed thereon.

In use, after collecting evidence from an individual in the usual manner, the individual baths, the collecting device being placed in the outlet of the bath instead of using a conventional bath plug, the lid member 24 of the collection device closing the upper part 18 of the housing 10. After bathing, the lid member 24 is removed, allowing bath water to enter the housing 10. The water entering the housing 10 is able to pass through the openings 16 of the strainer member 14, the water then flowing through the outlet of the bath in the usual manner. Particulate matter carried by the water entering the housing 10 is unable to pass through the openings 16 and is trapped within the housing 10.

After the bath has emptied, the lid member 24 is secured in position on the housing 10, trapping the collected matter within the volume 26, and the collection device is removed from the outlet of the bath and sent to a suitable laboratory for examination.

Relatively low density matter tends to float upon the surface of the bath water, and may adhere to the bath rather than enter the collection device. Such matter may be collected by wiping the bath using a cloth or wipe having a known DNA content and supplying the cloth or wipe to the laboratory with the collection device.

io Although the description hereinbefore is of the use of the device with a bath, the device may also be used with a wash basin or shower, different size devices being used in different applications. Where used with a shower, the lid component may be removed prior to showering to avoid forming a build up of water within the shower tray.

The device may be modified in a number of ways. For example, the lid member may be snap fitted rather than screw fitted to the remainder of the housing, and it may be held captive to the housing, if desired, thus reducing the risk of loss or contamination. Further, where evidence of a particular type is sought then the dimensions of the openings 16 of the strainer member 14 may be tailored to trap particles of the desired matter but to allow smaller matter to pass through the openings 16.

As water passing through an opening tends to form a vortex, and the vortex tends to separate the matter carried with the water so that relatively large particulate matter moves radially outward whereas smaller matter tends to occupy a more central position, the openings 16 of the strainer member 14 need not be of a uniform size, but rather may be relatively large adjacent the periphery of the strainer member 14 where the larger matter tends to collect 6 and smaller at a central part of the strainer member 14 where the smaller matter tends to collect without significantly impairing the ability of the device to collect evidence. Such an arrangement may be advantageous in that the speed with which water can pass through the housing is increased.

Further, if desired, one or more ribs may be provided over the surface of the strainer member 14 to assist in the collection of evidence, and/or a collection chamber may be provided radially outwardly of the strainer member 14 for use in the retention of relatively large matter.

Clearly, in order to ensure that the evidence is not contaminated, it is important to ensure that the volume 26 of the device is of known DNA content prior to use. The device will thus be supplied with the lid in its closed condition, removal of the lid to allow water to enter the housing only occuning after installation of the device in the outlet of a bath, shower, wash basin or the like. As the strainer member does not allow matter to pass therethrough, after use, the risk of contamination of the collected evidence is small. As the device is of known DNA content, the laboratory examination of the device, after use to collect evidence, can include a step of examining the collected evidence for DNA, ignoring the DNA known to be present in the device before use to collect the evidence.

Although the device is primarily intended for use by the victims of crime, conveniently in their own homes, the device may also be used by suspected perpetrators. In such circumstances, it may be desirable to locate the device in such a position as to ensure that the suspected attacker cannot remove, tamper with or impair the evidence collecting ability of the device. The device may also be suitable for use in other applications.

7

Claims

1. An evidence collection device comprising a housing having a closable lid, at least part of the housing being defined by a strainer member adapted to allow water entering the housing to escape therefrorn through the strainer member, but to collect, and retain within the housing, particulate matter carried by the water.

2. A device as claimed in Claim 1, wherein the strainer member includes io a plurality of openings, the openings being sufficiently small to ensure that human cells are retained within the housing.

3. A device as claimed in Claim 1 or Claim 2, wherein the openings of the strainer member are of a uniform size.

4. A device as claimed in Claim 1 or Claim 2, wherein the openings are of non-uniform size.

5. A device as claimed in Claim 4, wherein the openings in a central part of the strainer member are of smaller dimensions than those located towards the edges of the strainer member.

6. A device as claimed in any one of the preceding claims, wherein the housing is of dimensions to allow it to be received within the outlet of a bath, shower or wash basin.

7. A device as claimed in any one of the preceding claims, wherein the lid of the housing is securable in position on the remainder of the housing by screw threads.

8 8. A method of collecting evidence comprising locating an evidence collection device as claimed in any one of the preceding claims within the outlet of a bath, shower or wash basin, allowing the individual from whom evidence is to be collected to bath, shower or wash, allowing water to escape from the bath, shower or basin, the water entering the housing and passing through the strainer member, particulate matter carried into the housing being unable to pass through the strainer member and being retained within the housing, and closing the lid to trap the collected matter within the housing.

9. A method as claimed in Claim 8, further comprising a step of wiping the bath, shower or basin using a cloth or wipe of known DNA content to collect any matter adhering thereto.

10. An evidence collection device substantially as hereinbefore described with reference to the accompanying drawing.