While investigation of any case preservation of evidence is the top priority of those entrusted with gathering and collecting evidence. Evidence collection protocols apply to both pre-collection and post-collection evidence. If evidence is not properly preserved prior to collection, it may be contaminated or destroyed. If evidence is not properly preserved and stored prior to forensic analysis or testing, it may deteriorate, destroying or devaluing it as a source of information.
This article summarizes the ways and methods of handling and preservation of documents in criminal investigation cases. The proper care and preservation of documentary evidence, such as forged checks, anonymous letters, and comparison specimens (“standards”) of a suspect’s writing, is as much the responsibility of investigating officers as is the original investigation conducted for the purpose of obtaining or discovering these documents. Most officers realize the importance of securing evidence of this type, but many of them fail to thoroughly appreciate the necessity for careful handling and preservation during the time that these documents are in their possession.
The order to best preserve the document it is imperative that the following precautions be strictly observed and followed:
- Do not mark.
- Do not write upon original documents.
- Do not use pencils, pens, dividers, or erasures as pointers.
- Do not mutilate by creasing, repeated refolding, cutting or tearing.
- Do not carry the document in pocket for a prolonged period of time or handle excessively.
- Keep documents in envelopes or protective folders.
- Keep dry and away from excessive heat and strong light.
- Do not allow anyone except a qualified expert to make chemical or other types of test.
- Take documents to laboratory or expert at the earliest convenience.
These rules are primarily intended for the handling of questioned documents, such as handwritten or typewritten material about which there is some question concerning its author or manner of execution. However, they apply equally well to the preservation of specimens which are to be used for standards in handwriting and typewriting comparisons (i.e., specimens of handwriting or typewriting, the authorship of which is already established or admitted). In fact, any pieces of handwriting, typewriting, or printing which might conceivably form a link in the chain of circumstantial evidence surrounding an investigation should be given the same care as documents whose importance is already known and recognized. 
Handling and Transportation of Charred Documents:
Charred document (a document that has become blackened and brittle by burning or exposure to excessive heat is classified as charred document) can be expected in cases of accidental fire, intentional fire and arson, insurance and financial matters and leaking of examination papers, etc.
- Protect the crime scene.
- Switch off the fans and close the windows of the room in case of indoor crime scene. This will restrict flow of air and thereby burning of materials.
- Do not disturb the container in which the document is burnt until and unless the container is transported to the laboratory
- Stabilize the charred mass as far as possible using polyvinyl acetate in acetone solution (2-3 per cent) by spraying it gently over the charred masses as the charred documents are highly fragile.
- When there is a heap of charred mass, try to procure partially burnt documents from the inner middle part of the heap as un-burnt documents may be available due to lack of oxygen/incomplete burning.
- Do not try to remove the pages of stacks of paper. Lift them as it is. Scattered pages should be lifted using spatula and transfer to the glass sheet. Keep cotton over it and then transfer it to the cardboard box one by one.
- Get archival plastic sheets for preserving.
- Transport the cardboard box or corrugated box containing charred exhibits in the middle of vehicle as there is least chance of damage in this position.
- Great amount of patience is required to handle burnt or charred documents.
Handling and Preservation of Liquid Soaked, Dried and Frozen Documents:
- For wet, single-page select a suitable method such as submersion or drying, to unfold the document, or air drying, freeze drying, or pressing, and dry the document.
- For wet, multi-page documents, determine if the wet pages can be separated or unfolded without additional damage. This can be accomplished by submerging the documents in an appropriate liquid, such as water or mineral spirits. If the pages cannot be separated or unfolded, select a suitable drying process, such as air drying, freeze drying, or pressing.
- For dried documents, attempt to separate, if necessary, and flatten the pages using appropriate equipment, such as bone folders, picks, probes, and tweezers. Prior to or during the attempt to separate and flatten the documents, it may be necessary to rehumidify or resubmerge the documents. Rehumidification with appropriate fluids may be accomplished with an atomizer, humidity chamber, or both. When resubmerging the documents, an appropriate container and screen should be utilized.
- For frozen documents, treat the document same as dried documents. If time does not permit, thaw the documents and treat as wet documents.
- Do not air-dry glossy (coated) paper, parchment; immediately freeze.
Encapsulation of the documents upon completion, such as with polyester film or glass, or other procedures, such as parylene processing, may be advisable.
Special Precautions in Handling Anonymous Letters:
In anonymous letter cases, especially those in which the anonymous author writes a series of letters, the development of latent fingerprints on these letters may lead to his apprehension or identification. However, if latent prints are to be successfully developed, the following rules must be carefully followed.
In order that the only prints found on the letter shall be those of the anonymous writer, no one must touch the contents of the envelope. If a letter is suspected as being from the anonymous author, the best procedure is to bring it to the laboratory unopened.
There it can be opened and the contents removed by a technician in such a manner that the latent fingerprints will not be destroyed. If necessary, a copy of the contents can then be made for purposes of further investigation.
An alternative though less desirable procedure may be used if it is necessary to know the contents of the letter immediately upon receipt. Accordingly, the envelope may be slit with a knife, the contents removed with tongs or tweezers (in the same manner in which they would be removed at the laboratory), read, and without touching carefully replaced in the envelope.
Papers on which latent fingerprints may be found should be protected from rubbing and friction and kept away from excessive heat or moisture as the prints are easily affected by any of these factors. Moreover, because latent fingerprints on paper become indistinct or disappear entirely within a very short time, evidence should be brought to the laboratory immediately upon receipt. Fingerprint evidence in this type of case is important not only because it may be possible thereby to search through fingerprint files and identify the writer, but once a suspect is apprehended it forms identifying evidence in addition to the handwriting. 
- Hilton, O. (1940), “The Care and Preservation of Documents in Criminal Investigation”, Journal of Criminal Law and Criminology, Article 13, Vol-31;Issue 1 May-June.
- “Charred Documents” Chapter 18 [Online] (http://nicfs.gov.in/wp-content/uploads/2017/01/Charred-Documents.pdf) Accessed on 05/09/2019.
- “SWGDOC Standard for Preservation of Liquid Soaked Documents” [Online] (https://www.swgdoc.org/documents/SWGDOC%20Standard%20for%20Preservation%20of%20Liquid%20Soaked%20Documents.pdf) Accessed on 05/09/2019.