Tag Archives: electronic crime scene investigation

Small Scale Electronic Crime Scenes

Most frauds aren’t Enron.  As the ACFE tells us, most frauds encountered by practicing CFE’s are what I like to call “small crime-scene frauds” perpetrated by long time employees like Mary who works in a back office keeping the books, knows everything about the company, and who has been quietly embezzling lesser amounts of company funds without detection for the last fifteen years.  In today’s environment, Mary will be doing her work on a desktop computer, probably connected to a small network with internet access.  Mary’s workstation and the simple network supporting it constitute an electronic crime-scene to be investigated as thoroughly and with as much attention to detail as possible and accompanied by a full set of investigative documentation if there is ever to be any hope of obtaining a conviction (should Mary’s employer, your client, finally decide to go that way).

It goes without saying that the investigator or team of investigators to any crime scene, large or small, have the primary responsibility of protecting all the computer and related electronic evidence that might be useful in a future civil or criminal action. Evidence is where the CFE or other investigators find it. While crime scene evidence from personal and property crimes might be in plain view, computer and electronic evidence is subtler and might not be as evident or obvious at the scene.  In general, first responders at any scene can destroy critical latent evidence if they lack training in the proper identification, collection, and packaging procedures for the type of investigation. This means that both corporate security departments and law enforcement agencies routinely involved in such investigations specially train their personnel in computer and electronic investigative techniques. Much of the potential evidence at a small-scale scene might be circumstantial, but it could possibly be used to support the primary physical and direct evidence that a detailed investigation will later develop. A list of inappropriate purchases and related amounts found on Mary’s workstation at the crime scene could be persuasive to a jury if properly obtained.

Thus, education and preparation are major components of any successful crime scene search for electronic evidence. However, our corporate clients need to be made aware of what all law enforcement agencies know, that in-house or external security personnel, whose background might sometimes even include the performance of criminal crime scene searches, are usually not qualified for large or small-scale computer crime scene searches.

The basic steps involved in a small-scale computer site investigation include the following:

–Secure and protect the scene;
–Initiate a preliminary survey;
–Evaluate physical evidence possibilities;
–Prepare a narrative description;
–Take photographs of the scene;
–Prepare a diagram/sketch of the scene;
–Conduct a detailed search and record and collect physical evidence;
–Conduct a final survey;
–Release the crime scene.

Although a number of these steps also apply to crime scene searches for crimes involving misdemeanors and felonies, the orientation of their performance in the investigation of an electronic crime scene is more technical in nature. When a computer or some electronic device is suspected of having been used as a tool in the perpetration of a crime, normal evidence gathering techniques for computer forensics processing should always be followed. It does not matter whether the crime scene is also suspected of having been additionally involved in a separate fraud issue, a civil, or a criminal investigation; if a computer or other electronic device is involved, the steps will be the same in all cases.

It is also essential that the organization’s computer personnel be excluded from the crime scene. Most computer specialists are not familiar with computer forensics techniques and individuals among them could have been involved in the crime, wittingly or unwittingly. Additionally, security must be provided for the area while the investigation is proceeding. Any employees or visitors who subsequently enter the scene need to be identified.  Try to identify in writing anyone who has routine access to the site or anyone who might have a reason to be involved with the scene generally. Do not rely on your memory alone, as it will not sufficiently support you in a court of law.

Computer and electronic evidence usually takes on the same general forms with which we’re all familiar: computer hardware, peripherals, cell phones, hand held devices, various storage media, digital cameras, and the list goes on. The investigator will have a general knowledge of the types of evidence that can be collected from each of these devices; however, s/he must be prepared for new devices showing up at any crime scene at any time. A cautious walkthrough is a good first step to get a feel for the complexity of the site. In addition to a workstation, several additional workstations or areas might become part of the investigation. Keep in mind that due to the networking configurations of even today’s smallest systems, remote sites might probably be involved in the investigation.

The investigator(s) should strive to maintain a continuing level of control of the situation and of the physical site during the investigation.  An inventory log and chain-of-custody form should be completed and photographs made of all relevant devices and related electronic evidence. Specific activities that might be included in this phase of the investigation include:

–Determination of all the locations that might need to be searched;
–Look out for any specific issues that need to be addressed relating to pieces of hardware and software;
–Identification of any possible personnel and equipment needed for the investigation but not yet on-site;
–Determination of which devices can be physically removed from the site;
–Identification of all individuals who have had access to the computer or electronic resources material to the investigation.

The evaluation of physical evidence is a continuation of the preliminary survey and may not be perceived as a separate step. After the site is thoroughly photographed, a more detailed search can begin. Before any devices are handled, remember that fingerprint evidence might become evidence in establishing who used these devices. The smallest, most insignificant appearing piece of evidence might clinch a case. Any network capability and connections to the computer site must be identified. Networking can broaden any investigation considerably. If there is an internet connection, it can become a worldwide investigation involving various internet service providers and the possibility of subpoenas. Cell-phone evidence may involve various telephone network carriers and additional subpoenas.  Prioritize the evidence collection process to prevent loss, destruction, or modification. Focus first on items easily identifiable and accessible and proceed to identified out-of-sight evidence. Look for the obvious first, the suspect might have been sloppy.

A journal or narrative must be prepared concerning the investigation and the crime scene search. Anything and everything is important when conducting the scene investigation. Remember that the defense attorney is going to query any witnesses on the most obscure item possible. A technique suggested by the ACFE is to represent crime scenes in a “general to specific” scheme. Describe the site in broad terms and then get very specific with details. A sound idea is to cross-reference a chronological journal with the photographic evidence and a chain-of-custody form. The narrative effort should not degenerate into a sporadic and unorganized attempt to recover physical evidence. Under most circumstances, evidence should not be collected while developing the narrative. The narrative process can be accomplished by using audio, video, or text. Remember the axiom “haste makes waste.”

Developing a photographic profile of the crime scene is a requirement for any computer forensic investigation no matter how small. Photographs should be taken as soon as the incident scene is secured and before any computers or electronic devices are moved. Photographs should be taken from all angles of the physical site. Close-ups of cable connections for all devices should be included. Note these cables will need to be separately tagged in another step. Any video screens displayed would be photographed. The photographic effort needs to be recorded in a photographic log.  Photographs should be taken as soon as possible to depict the scene as it is observed before anything is handled, moved, or introduced to the scene. Photographs allow a visual permanent record of the crime scene and items of evidence collected from the crime scene.

A diagram or sketch establishes a permanent record of items, conditions, and distance/size relationships. They also supplement the photographic record. Usually a rough sketch is drawn at the crime scene and is used as a model for a complete, formal document that would be completed later. The sketch can be coordinated with any logs or journals via a numbering scheme. Sketches are used along with the reports and photographs to document the scene. A crime scene sketch is simply a drawing that accurately shows the appearance of a crime scene.

The CFE will usually have a general idea from discussions with the client as to the types of evidence that s/he will find at the incident scene. A checklist can be developed that will identify most types of computer and electronic evidence that might be at a small-scale crime scene. The major difference between investigations will probably be the size of the computer system and the amount of disk storage that will need to be secured or imaged. Seizure of electronic devices, such as cell phones and iPads, should not pose any special problems due to their small size. It might be necessary to determine the amount of disk storage records that need to be copied or imaged for later forensic analysis. On large data bases or for data in the cloud it will be next to impossible to copy or image the entire storage device. In these cases, a forensic examination might have to occur partly at the crime scene and partly off-site once the required permissions for data access are received from the data owners of record.

Conflicts in documentation can cause considerable grief in a court of law. Also, if a computer system is to be reconstructed later, cable connections and maps must be precise. There are four basic premises to the search, recording, and collection phase of a small- scale investigation. These premises are as follows:

–The best search options are typically the most difficult and time consuming;
–The physical evidence cannot be over-documented;
–There is generally only one best chance to properly perform the investigative task;
–Cautious searching of visible areas and identification and searching of relevant off-site areas is crucial.

After the investigative team has completed all tasks relating to the search, recording, and collection phases at the small-scale crime scene, a critical review should be conducted to ensure that nothing has been missed. This is the last chance to cover all the bases and ensure nothing has been overlooked. The investigators must ensure that they have gone far enough in the search for evidence, documented all essential things, and made no assumptions that may prove to be incorrect later.

–Double-check documentation to detect inadvertent errors;
–Check to ensure all evidence is accounted for before leaving the crime scene;
–Ensure all forensic hardware and software used in the search is gathered;
–Ensure possible hiding places of evidence and difficult areas for access have not been overlooked;

An incident scene debriefing is the best opportunity for personnel and participants to ensure the investigation is complete.

The last step in the evidence investigation phase for a small-scale crime scene featuring electronic evidence is to release the incident scene back to its owners. The release is accomplished only after completion of the final survey. The individual investigator or team should provide an inventory of the items seized to the client owner/manager of the scene. A receipt for electronic evidence must be completed for any devices seized. A formal document should be provided that specifies the time and date of the release, to whom released, and by whom released.