CAID: The Child Abuse Image Database, Grading and Challenges

The Child Abuse Image Database (CAID) is a national law-enforcement database used in investigations involving indecent images of children.

CAID allows police and the National Crime Agency to identify images and videos already known to law enforcement, categorise material, reduce repeated viewing by investigators and assist with victim identification.

In criminal investigations involving indecent images, CAID evidence can play an important role in establishing the number and category of images said to have been found on a device.

However, CAID categorisation is not necessarily beyond challenge. The way images have been identified, categorised and described should be considered carefully where it may affect the prosecution case or sentence.

What Is the Child Abuse Image Database (CAID)?

CAID is a secure national database used by UK police forces and the National Crime Agency.

It contains images, videos and associated data relating to child sexual abuse material encountered by UK law enforcement and enables information to be shared and compared across different investigations.

Among other things, CAID is designed to:

• identify material already known to law enforcement;

• reduce the need for police officers repeatedly to view the same distressing material;

• assist with categorisation;

• support victim identification;

• assist investigations into suspected offenders; and

• provide information which can be used in criminal proceedings.

CAID has been in operation nationally since 2014.

How Does CAID Identify Known Images?

Digital files can be identified using a hash value.

A hash can be understood as a form of digital fingerprint generated from a file. Investigative software can compare the hash values of files found on a seized device with hash values associated with material already held within CAID.

Where a matching image is identified, investigators may be able to establish that the same material has previously been encountered and categorised by law enforcement.

This can make the examination of large volumes of digital material considerably more efficient.

A file which is not recognised by CAID is not necessarily lawful or irrelevant. It may instead require separate examination and categorisation by investigators.

How Are Indecent Images Categorised on CAID?

For sentencing purposes, indecent images are generally divided into Categories A, B and C.

Broadly:

Category A includes images involving penetrative sexual activity, sexual activity with an animal or sadism.

Category B includes images involving non-penetrative sexual activity.

Category C comprises other indecent images which do not fall within Categories A or B.

The category can be important because it may affect charging decisions, the assessment of seriousness and the eventual sentence.

What Is a “Trusted” CAID Grade?

CAID is designed to avoid every investigator having to recategorise images which have already been assessed.

An image can acquire a confirmed or “trusted” categorisation after the same category has been independently assigned by officers from three separate UK police forces.

Once an image has a trusted CAID categorisation, that categorisation can ordinarily be relied upon when the same image is encountered in later investigations.

This system reduces duplication and limits unnecessary repeated exposure of investigators to disturbing material.

How Is CAID Used During a Police Investigation?

Where digital devices are seized, forensic tools may compare files on those devices with material held within CAID.

Investigators may then produce a Streamlined Forensic Report (SFR) identifying, among other matters:

• the number of recognised CAID images;

• the categories into which they fall;

• representative examples;

• descriptions of those examples; and

• relevant information about the devices and files examined.

CAID may therefore play an important part in determining the evidential picture at an early stage of an investigation.

However, it remains important to consider matters such as how the files came to be on the device, whether they were deliberately accessed, whether they were deleted or cached, and whether the suspect knew of or controlled them.

CAID categorisation does not itself resolve those separate questions.

How Is CAID Evidence Used in Court?

The courts generally do not need to view every image personally.

In R v Pinkerton [2017] EWCA Crim 38, the Court of Appeal emphasised the importance of applying the established sentencing categories rather than creating subjective additional classifications.

The Court also recognised that, given the existence of the database and proper categorisation, it should ordinarily be unnecessary for sentencing judges themselves to view the material except where there is a particular reason to do so.

Current CPS guidance similarly provides for representative images to be described in streamlined forensic material, with viewing normally unnecessary unless a genuine issue requires it.

This approach is intended both to promote consistency and to avoid unnecessary repeated viewing of abusive material.

Can CAID Grading Be Challenged?

Yes.

Although CAID provides an important national system for categorising known material, a categorisation should not simply be assumed to be correct where there is a proper basis for challenge.

Possible issues can include:

• whether an image has been placed in the correct category;

• whether the description accurately reflects what is depicted;

• whether the image is in fact indecent;

• whether the apparent age of the person depicted is disputed;

• whether the material falls within the statutory definition;

• whether the prosecution has correctly interpreted the forensic evidence; and

• whether the categorisation materially affects charge or sentence.

At Berkeley Square Solicitors, we have acted in cases where police categorisation has been challenged successfully.

Where grading is genuinely in dispute, careful examination of the prosecution material may be required and, in an appropriate case, independent expert evidence may assist.

Why Does Correct Categorisation Matter?

The category assigned to an image can affect the seriousness with which the case is treated.

For sentencing purposes, Category A is the most serious category, followed by Categories B and C.

An incorrect categorisation can therefore have a material impact on how the prosecution presents the case and on the eventual sentencing exercise.

Further information on categorisation and grading can be found in our FAQs on Sentencing and Category A, B and C Illegal Images Explained

CAID Does Not Determine Whether a Person Is Guilty

A CAID match may assist in establishing what a file contains and how it has previously been categorised, but it does not necessarily determine whether the suspect committed an offence.

Separate issues may still arise concerning:

• knowledge;

• possession;

• control;

• deliberate downloading;

• automatic caching;

• deleted files;

• unsolicited material;

• access by other users;

• cloud storage;

• file-sharing software; and

• the reliability and interpretation of the forensic evidence.

Those issues can be just as important as the categorisation itself.

How Berkeley Square Solicitors Can Help

Indecent images investigations frequently involve detailed digital evidence and technical issues. We advise clients on matters including

• CAID evidence;

• Streamlined Forensic Reports;

• categorisation disputes;

• digital forensic evidence;

• downloaded and cached material;

• deleted files;

• possession and knowledge;

• representations seeking to avoid charge;

• independent expert evidence;

• trial and sentencing advice.

Following an initial consultation, we can explain the investigation process, identify the important evidential issues and advise on the steps which should be taken.

Enquiries From Partners and Family Members

We are frequently contacted by partners, family members or close friends of someone who has been arrested or is under investigation.

We can explain the general process and, subject to the usual professional requirements and the client's authority where necessary, arrange to advise the person concerned directly.

Speak to an Indecent Images Solicitor

If you are being investigated in connection with indecent images and require specialist advice, contact Berkeley Square Solicitors for a confidential consultation.

Our London criminal defence solicitors have extensive experience dealing with indecent images cases, CAID evidence and digital forensic issues.

Call our London office on 020 3858 0851.

You can also read our guides to indecent images offences, sentencing and categorisation, deleted files, Streamlined Forensic Reports, and defending indecent images allegations.