Forensics Chapter 16

In addition to comparing words and letters, what else must a document examiner know how to do?

Detect alterations, obliterations, erasures, and additions in documents.

What is meant by a questioned document?

Any document whose authenticity, source, or authorship is in dispute.

According to document examiners, do any two individuals write exactly alike?

No, no two people’s handwriting is exactly the same.

Variations in writing occur in what categories?

Angular connections, letter formations, slant, speed, spacing, and pressure.

What is an exemplar?

A known sample of handwriting used for comparison with a questioned document.

What is meant by natural variations?

Normal, minor differences that occur in a person’s handwriting each time they write.

Why is it important to find standards that date closely in time to the questioned documents?

Handwriting can change over time, so recent samples provide more accurate comparisons.

When a writing sample is requested of someone, that person may intentionally try to alter their sample. How might an investigator avoid the deception?

Have the suspect write multiple times, dictate different texts, and collect writings done naturally.

If a typewriter is involved, two questions of an examiner are frequently asked. What are those questions?

What make and model produced the questioned document, and can a specific typewriter be identified as the source?

How are individual characteristics imparted to a typewriter?

Through wear, misalignment, defects, and damage to typefaces.

When a photocopier, printer, or fax is used to commit a forgery, how many reference samples are generally obtained from the machine for comparison?

At least ten samples.

How might a copier be individualized?

By unique marks, scratches, and mechanical defects it leaves on documents.

What is a transmitting terminal identifier (TTI) and how can it assist document examiners?

A header printed by fax machines that identifies the sending device, which helps trace documents.

What are some class characteristics that might be identified by a document examiner if a suspect’s machine is not available?

Type style, font, spacing, margins, and general printing technology.

What are some ways criminals attempt to alter documents?

Erasing, overwriting, adding material, chemical treatment, or cutting and pasting.

What is an erasure?

The removal of writing by scraping, rubbing, or chemical means.

What is infrared luminescence and how can it help document examiners?

Light emitted by inks under infrared radiation, which can reveal alterations and differences in ink.

What is obliteration?

The crossing out or covering of writing to hide the original content.

What does Figure 16-3 show?

An example of obliterations and how examiners can reveal the original writing.

What are charred documents?

Documents damaged or destroyed by fire.

How can writing on a charred document be revealed?

Using infrared photography or digital image processing.

How is Adobe Photoshop a help to document examiners?

It enhances and clarifies faint or damaged writing on documents.

What are indented writings?

Impressions left on underlying sheets of paper when pressure is applied while writing.

Indented impressions are most visible when viewed under what lighting?

Oblique (angled) lighting.

What are some techniques used to analyze ink?

Thin-layer chromatography (TLC), spectroscopy, and chemical testing.

What does tagging allow for?

Tracing ink back to its manufacturer and batch, aiding in source identification.

Document examiners are also interested in paper. What are some features that allow for distinguishing between different types of paper?

Watermarks, fiber composition, color, thickness, and additives.

What does a sound spectrograph do?

It produces a visual representation (spectrogram) of sound frequencies over time.

What are voiceprints?

Graphical representations of speech patterns showing frequency, intensity, and time.

The vocal cavities consist of what?

The throat, mouth, and nasal passages.

Articulators consist of what?

The tongue, lips, teeth, and soft palate.

What three parameters of speech are portrayed in a voiceprint?

Frequency, intensity, and time.

Look at Figure 16-11. Can you match the upper left voiceprint with one of the five suspects?

Yes, by comparing frequency and speech pattern details to the suspects’ samples.

How many speech sounds must match to make a positive identification?

At least ten to twelve speech sounds.

True or False……Forensic voiceprint technology is widely accepted and welcomed into courtrooms across the United States.

False, it is controversial and not universally accepted in court.