CSI - Photography

One of the essential skills of a CSI is to be able to record photographically any subject, in any position or condition. To this end the initial CSI training devotes many weeks to the theory and practice of taking photographs and teaching the techniques which will achieve these goals.

Scenarios are devised which simulate the types of scenes which the CSI is likely to encounter during their working day. The CSIs have to demonstrate their ability to produce perfect images, of evidential quality, in conditions such as total darkness, cramped, noisome rooms, bodies in difficult positions, etc.

In order to achieve professional, results we use top quality equipment. Our standard camera kit is a Nikon D1X with an SB28 speedlight and three Nikon lenses. In addition there are spare batteries, various filters, spare memory cards and the whole kit is carried in a camera back-pack. An identical set is issued to every member of the Scientific Support unit and is also used in the photographic studio at police headquarters.

The digital images that are taken are subject to a rigorous system of storage to ensure the integrity of the pictures.

The camera’s CompactFlash card is first cleared before use. All images taken at a crime scene are retained in sequential order and, even if a mistake is made, they are never deleted. Images are therefore recorded sequentially, from number one to the final image, with no numbers missing.

The camera’s software records the time and date the image was taken, along with the lens, aperture and shutter speed. This ‘metadata’ is encoded with the digital image in the electronic file.

Once the scene is concluded or, at lengthy crime scenes at a natural conclusion (such as a meal break, or the end of the day), the images are immediately saved to a WORM (Write Once Read Many) digital media. Currently this WORM media is a CD-R. In the foreseeable future, however, it will become a DVD-R when the current cameras are replaced with models which record images of even larger file sizes.

The equipment used to record the CD-R is an Apacer portable DVD drive. This item copies the data from the CompactFlash card onto the CD-R, checks all the files to ensure that the data on each is identical, and finalises the disc so that the data cannot be added to.

Once done, we then have the main evidential copy of the images, timed, dated and stored onto a media which prevents it being altered or added to. We then re-format the CompactFlash card in the camera and re-use it at the next scene.

The CDs are stored carefully in cases and unsealed evidence bags until the CSI next returns to police headquarters. Once in the office a unique file reference number is generated and the files copied onto the CSI stand-alone network.

This electronic copy of the images is used to produce photographs for court purposes. As soon as the images are copied onto the network the original CD is sealed into the tamper evident exhibit bag and stored at a location remote to headquarters. All of these CDs are checked and the serial numbers of the exhibit bags noted by the departmental head before storage.

The final part of the process is that all of the files on the network are backed up onto DVDs which are stored in a fire safe for disaster recovery purposes. The sealed CDs can only be opened on the authority of a Deemster, or other presiding member of the judiciary, should a doubt be raised that an image had been altered before printing. This process fully complies with the Association of Chief Police Officers (ACPO) guidelines for the evidential use of digital images.