ESDA

ESDA is a tool used in questioned document cases. But how it works?
This has been explained in this ppt.

1. ELECTROSTATIC DETECTION APPARATUS (ESDA) Presented By : Harshita Niranjan Criminology Volunteer APPLIED FORENSIC RESEARCH SCIENCES

2. CONTENTS INTRODUCTION PRINCIPLE HISTORY STORY BEHIND COMPONENTS ADVANTAGES DISADVANTAGES APPLICATIONS REFERENCES

3. Electrostatic Detection Apparatus or ESDA is a document analysis equipment commonly used in the examination of questioned documents. It is mainly used to perform non-destructive examinations for indentations, i.e., the process do not damage the paper. INTRODUCTION

4. ESDA uses applied charges and toner to visualize areas of indented writing. It uses the principle that indented areas of the document carry less negative charge than surrounding areas. This causes the toner used in the ESDA to be attracted to these areas, revealing indentations that are present. PRINCIPLE

5. ESDA was discovered 40 years ago by Foster and Freeman . It was originally a part of a research project. Its first use was identifying fingerprints on fabric which proved to be a huge fail, although making it successful on a large scale for its secondary use, that of detecting indented writing. HISTORY

6. The popularity of ESDA reached peaks overnight following a raid on a London bank. Originally a part of a research project, ESDA was suddenly used by police to examine a note handed by the robber to the bank teller demanding cash . ESDA revealed the indentations which came out to be of a telex message drafted to someone in Canada. The message was a pleading to send money to an address in Surrey. This led to the arrest of the man further popularizing the ESDA technique. STORY BEHIND

7. Main Unit Reel Holder (Imaging Film) Corona Wand Mains Power Adapter COMPONENTS

8. 1. Latent indented writing can be detected and preserved, which otherwise is not visible by oblique light. 2. Indented writing is revealed which usually is unnoticeable to the naked eye. 3. It is a non-destructive technique and hence does no damage to the paper during the examination process. 4. It is a sensitive technique as indentations from up to 7 layers of paper beneath the original writings are recovered. ADVANTAGES

9. 1. It is not suitable for examination of loose paper such as newspaper. 2. This technique cannot be performed on glossy paper such as that of a magazine. 3. If a document gets wet by any liquid, it will completely destroy the ESDA impressions. DISADVANTAGES

10. To detect cheque forgery. To identify traced forgery. To find existence of a ransom note. To investigate a suspected anonymous letter. APPLICATIONS

11. https://www.questioneddocuments.com/esda/ https://www.fosterfreeman.com/product/qde-products/678-esda-history.html https://www.cbsnews.com/news/48-hours-preview-the-fascinating-history-of-the-ransom-note/ https://english.jagran.com/india/delhi-man-steals-cheques-from-bank-drop-box-new-fraud-raises-concern-over-its-safety-10022295 REFERENCES

12. THANK YOU