Forensic Information System for Handwriting (FISH)

BY SIFS India | December 07, 2022

Forensic Information System for Handwriting (FISH)

FISH stands for Forensic Information System for Handwriting.

This is a computer-based mission-critical system that allows a document examiner to scan, digitize, measure and store questioned and known handwriting.

So basically, FISH is a database that enables document examiners to scan and digitize text writings such as threatening correspondence. 

Purpose of Forensic Information System for Handwriting 

For the analysis of the documents created by typewriters, fax machines, or printers, examiners may rely on various types of databases created for comparison purposes.

While doing an analysis of handwriting, examiners compare the samples provided from a particular population.

The forensic Information System for Handwriting unit's main purpose is to digitize, scan and store the handwritings which are questioned or known for searching the writing against previously stored material in a short amount of time.

Forensic Document Identification Using FISH

When conducting examinations, forensic document examiners must have known specimens to which they compare the material in the questioned documents.

These samples are collected from various known sources, such as by person or any printed document by printers or typewriters.

In cases the handwriting samples that are involved are usually divided into two types: requested writing specimens and collected writing specimens. 

Requested writing specimens are dictated by the investigator to the writer.

These specimens are made under carefully controlled conditions as the writer is being closely monitored.

Collected writing specimens, however, are writings that were completed by the subject prior to the investigation.

These are a good sources of writing specimens that may include items such as letters, checks, signed receipts, medical records, tax records or other signed legal documents.

Forensic document examiners play a major role while investigating any questioned or known handwriting samples. These forensic document examiners may work as private under any agencies.

Many techniques and tools are used to examine the handwriting samples that are questioned and known handwritings. Whereas document that are created by typewriters or printing machines rely on various databases for their examination.

What is QDU?

QDU stands for Questioned Document Unit. This unit provides forensic support to the Federal Bureau of Investigation (FBI), and state, and local law enforcement agencies by conducting forensic examinations on evidence collected during the investigation.

Federal agencies with QD unit are:

1. Federal Bureau of Investigation (FBI)

2. Immigration and Customs Enforcement

3. US Secret Service

4. US Army Crime Lab

5. Internal Revenue Service (Forensic Laboratory)

These units are responsible for maintaining extensive databases of bank robbery notes, anonymous letters, fake checks, and ink depositions. 

Forensic Information System for Handwriting (FISH) is maintained by the U.S. Secret Service, this database enables the document examiners to scan and digitize text writings such as threatening correspondence.

Role of US Secret Service in FISH System in Forensic Analysis? 

The United States Secret Service is a storied law enforcement organization that has ties to many different areas of forensic science.

The forensic service division, which is a part of the Secret Service has a highly advanced forensic laboratory, as well as the largest ink laboratory in the world.

The Secret Service has a forensic specialists and examiners that can handle forensic evidences in many capacities and at many different levels.

They will be able to examine the evidence, develops leads with investigations, and offers experts testimony in the courts. It has accreditation by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board.

This Secret Service Lab also have questioned document department, where they are able to determine the legitimacy of documents based on forensic analysis.

Some of the best experts works with the Secret Service. The visual formation area uses many different types of technologies including forensic photography, audio and image enhancement, voice identification, stimulations, 3-D modelling, graphic arts, and more.

The United States Secret Service, Forensic Information System for Handwriting (FISH) is a highly- sensitive, law enforcement database.

FISH records are protected from unauthorized access through appropriate administrative, physical, and technical safeguard.

In addition, extended access rights are assigned to those with a specific need. Forensic Information System for Handwriting (FISH) is exempted in whole or part from public use under 36 CFR 1256.85 (a) Disclosure of Records (National Archives and Records Administrations Code of Federal Regulations).

This information related to law enforcement investigations, and the data depicts threatening correspondence towards president of the United States, high level government and foreign officials protected by the United States Secret Service, Federal, State and Local Law enforcement.

Advancement in Handwriting Evidence Analysis

There are several systems that helps in examination of handwriting samples with multiple functionality that includes both interactive tools and techniques to aid the document examiner and automatic writer recognition functionality. These are as following:

FISH System 

Several computer software tools to assist document examiners in their analysis techniques were developed in the 90’s. one particular effective system known as FISH for Forensic Information System for Handwriting was developed by German Law enforcement.

FISH enables interactive work with the document examiner so as to enable retrieval of the closest match from a larger database of the samples of handwriting.

WANDA Architecture

As successor to FISH system, WANDA is also a computer-based identification for writers on the basis of digitized piece of handwriting which is a challenging task for pattern recognition.

WANDA is an open framework for electronic data processing.

This framework provides generic interfaces for ‘plug-in’ applications in common data standards and identification procedures. It also allows future updates with the state-of-the-art technologies.


To study the individuality of the handwriting, an information processing model of handwriting examination was developed.

This led to a system for forensic document examination known as CEDAR-FOX. In autonomous mode it performs several operations including writer verification, writer identification and signature matching.

Future Prospects and Challenges

Research into computer methods in forensic document examination is still at an early stage.

The research is mainly concerned with tools and techniques for the comparison of writing samples to identify the authorship.

There is considerable further research required to provide scientific detailed scientific evidences of the nature of handwriting individuality.

Further research is needed to provide scientific evidence and tools to identify forged handwriting and as well as altered or modified writing.

In addition, computers could provide impressive assistance in the restoration or decipherment of damaged or partially destroyed documents.