So you've seen CSI and Silent Witness but have you ever wondered what a police forensic department is really like?

From crime scene attendance to evidence analysis and through to crime scene reconstructions, the forensic department are more than what you may have seen on TV or in films. There are so many roles and teams applying science to policing and supporting investigations across the Thames Valley.

Find out more about each of the teams in our forensics department below.

Crime Scene Investigators are who would spring to mind when you mention forensics. These are the individuals who will visit the crime scene and where necessary, wear a white suit, mask and shoe coverings whilst laying out yellow number markers and taking photos of evidence in situ.

CSIs will examine a crime scene to document and recover evidence that could potentially link the scene to a suspect or that could help to prove or disprove someone’s involvement in a crime. They will also photograph the scene to show the layout and to add context to forensic staff and investigators who won’t be at the scene.

Primarily, they use a variety of methods to develop and recover physical evidence such as fingerprints, shoeprints and toolmarks. They also examine scenes for the presence of body fluids, e.g. blood or saliva and recover samples from surfaces that have been handled that could be sent for DNA profiling.

If an exhibit is found at the scene of a crime that is likely to have been handled by a suspect but cannot be examined by the CSI using their fingerprint powders, it is sent to the laboratory for examination. Fingerprints can often be difficult to spot with the naked eye, it is essentially sweat left on a surface and so the Fingerprint Development Laboratory have specialist chemicals, light sources and analytical equipment to make the prints more visible and use advanced photography equipment to capture the fingerprint detail in the best possible image quality.

Once a fingerprint has been obtained and developed to the best possible image quality, the Fingerprint Bureau analyse, compare, search and identify samples against prints held on the National Fingerprint Database or prints provided by people who can be eliminated, for example the homeowner of a burglary. The Bureau don’t just look at fingerprints, they can also identify and compare unique detail on palm prints, the sides of your hand and even footprints.

With so many different fingerprint patterns and variations to compare, an eye for detail and patience are key in this team. It takes around 5 years of training to become a competent fingerprint expert.

Our footwear unit don’t just specialise in footwear marks, they also analyse marks that have been left by tools, for example those used to prise something open or to cut something.

Staff in the footwear unit will analyse footwear marks recovered from crime scenes and compare these against impressions taken from shoes seized from suspects, looking at sole patterns, size and even how worn the sole is.

They also compare recovered footwear marks to over 40,000 different shoe marks on the national database to give detectives and officers guidance on the specific type, brand and model of footwear that offenders are likely to have been wearing.

When it comes to analysing toolmarks, the team will recreate marks that a specific tool would have left and compare it to those found at the scene using microscopes.

Our Screening Unit conduct intricate examinations of clothing and objects involved in crime in a controlled laboratory environment. This work often involves the use of microscopes and specialist light sources to locate the available evidence. These items can be searched for the presence of body fluids, such as blood and saliva. If found, these will be sampled and can be sent for DNA profiling at an external forensic laboratory.

Using a variety of methods, they will also recover samples from items of clothing to test for the presence of DNA or target specific areas of an item to potentially identify who has touched or handled it. They can also recover hair and fibres from items which can be submitted to an external forensic laboratory for further analysis.

This is a small team, who have extensive operational experience of the investigation of drug dealing. Their role is to provide the Courts with an impartial opinion from the evidence supplied to them in order to support prosecutions for cases involving the supply of drugs.

This will typically include considering data from seized mobile phones including the use of language within messages, the amount of cash seized and evidence provided by external forensic laboratories This could be the type of drug seized, the quantity of individual drug wraps and the weight.

This evidence is considered and a statement of opinion is produced that puts all the relevant evidence together into the context of drug dealing which will also provide the approximate value of any seized drugs.

From editing 999 calls to downloading voicemail messages, retrieving and converting CCTV to redacting video interviews, this team of digital media experts support investigators with all things video and audio.

The Forensic Audio and Visual Unit support investigators in retrieving and downloading digital evidence and then making the most of the evidence they have either by enhancing footage or creating image comparisons between something seen on CCTV and something that was later seized from a crime scene.

Digital media presentations can be incredibly impactive when investigators are presenting the evidence in court.

The HTCU are pivotal to modern policing as digital investigations grow year on year. This specialist team secure digital evidence from the electronic devices that are now used so frequently in our day-to-day lives.

The team manage the retrieval of data and analysis of information from mobile devices and computers. From supporting on line investigations, downloading data from electronic devices through to dealing with large scale computer downloads to support complex and small scale investigations, the team support policing investigations from crime scene to court.

The Imaging Unit and Crime Scene Surveyors offer investigators a wide range of options in reconstructing crime scenes.

Their work can include capturing panoramic or 360 images from the crime scene and then stitching them together so they can be walked through like Street View. They can also add context to maps, visualising a route taken by offender or displaying where evidence was found.

They can use laser scanning technology to capture the minute detail of a crime scene to create a 3D ‘virtual fly-through’ of the scene. These produce a precise animated reconstruction that can be moved almost like a video game, and can then demonstrate exactly where specific evidence was recovered and overlay it with images taken by CSI at the scene or with CCTV footage that has been seized.

VIPER stands for Video Identification Procedure Electronic Recording and is the replacement procedure of the ID parades or ‘line ups’ that are traditionally associated with policing.

This team compile video images of suspects and people who match the description given by a witness and facilitate viewings with the witness to establish whether they can identify the person that they saw.

Our Facial Imaging Officers use specialist software to create a facial composite image of a suspect based on a description provided by a witness.

You will probably have seen one of our efit images in the press as a result of appeals that we have shared to help us to identify a suspect.

The Quality Team are responsible for all aspects of the implementation and maintenance of forensic accreditation and regulation across our Forensic Investigation Unit.

On the whole, accreditation in forensics is about assuring the quality and validity of evidence entering the Criminal Justice System.

Our team ensure that we are satisfying and complying with the Forensic Science Regulators (FSR) Codes of Practice and Conduct. Standards in place in the department include ISO17025 General Requirements for the Competence of Testing and Calibration Laboratories and the Forensic Science Regulators Codes of Practice and Conduct (FSR CoPC) and we are working towards ISO17020 Requirements for the Operation of Various Types of Bodies Performing Inspections. Third party accreditation bodies independently confirm that we are meeting the requirements of the standards.

These teams are all supported by dedicated police staff personnel who manage the administrative needs of the department as well as the authorisation for submissions of evidence, which is often into the thousands of items every month.

If you’re interested in working in our Forensics department, take a look at the roles listed on our careers website. You can even sign up to be alerted when new jobs are added.