Forensic Unit 3 Chapter 16 and 18 Review

What is a TTI. Name 2 ways in which it is useful in document comparison

The header that fax machines print at the top of each fax page. They can be prepared and placed in the right place but a microscopic examination reveals significant characteristics that distinguish it from a real TTI

What is digital imaging? How is it useful for analyzing fingerprints

The process through which a picture is converted into a series of square electronic dots known as pixels. The pic is manipulated by computer software that changes the numerical value of each pixel. The image is enhanced and helps the examiner view fine details and compare it

What constitutional principle did the Supreme Court address in Gilbert v California, and how did the court rule

The taking of handwriting exemplars violating rights. It does not violate the 5th amendment

What 2 questions are documents examiners most often asked about typewriters

1. can the make and model be identified to type of questioned document 2. can suspect typewriter be identified as making questioned document

Describe 2 situations in which a document examiner may be prevented from coming to a positive conclusion about a questioned document

1. insufficient number of known writings available for comparison 2. questioned document only has a few words that are written in unnatural form or carefully written to disguise the natural style

30 year old murder solved

1978, 61 year old Carroll Bonnet stabbed to death in apartment. Police collected latent fingerprints and palm prints from the bathroom and then the victim's car was stolen. The car was found in Illinois. Latent fingerprints from the scene and car were searched in local and state fingerprint files and fingerprint requests were sent outside of Nebraska, but no matches were found. In late 2008, the prints were searched against IAFIS. In less than 5 hours, there was a list of suspects. The prints were examined and linked to Jerry Watson who was in prison on burglary charges. He lived a few blocks from where the victim's car was found. His DNA matched the DNA at the crime scene and was sentenced to life in prison in 2011

When comparing sample writing to a suspect document, the age difference between the documents should be no more than

2-3 years

What are dermal papillae and how are they related to fingerprints?

A cross section of skin reveals a boundary of cells separating the epidermis and dermis. The shape of this boundary, made up of dermal papillae, determines the form and pattern of the ridges on the surface of the skin. Once they develop, the ridge patterns remain unchanged throughout life.

What is the first fundamental principle of fingerprints?

A fingerprint is an individual characteristic because no two fingers have yet been found to possess identical ridge characteristics.

What is the second fundamental principle of fingerprints?

A fingerprint will remain unchanged during an individual's lifetime.

What are exemplars? Why are they important for document examination

An authentic sample used for comparison purposes, such as handwriting. It shows the examiner the range of natural variations in a suspect's writing characteristics.

Name at least 5 characteristics of handwriting in which one might expect to encounter variations between individuals

Angularity, slope, speed, pressure, letter and word spacings, relative dimensions of letters, connections, pen movement, writing skill, finger dexterity

What is a questioned document

Any document about which some issue has been raised or that is the subject of an investigation

What is an AFIS? What is the heart of AFIS technology?

Automated Fingerprint Identification System. ability of computers to scan and digitally encode prints to be subject to high-speed computer processing

When using AFIS who makes the final verification of a print's identify

Certified examiner

Briefly describe how the criminalist should handle prints on small objects

Covered with cellophane so it will be protected

Under what conditions is digital imaging not effective in enhancing latent fingerprints

Digital imaging is not effective in enhancing latent fingerprints if details of the print do not exist on the original images

A single handwriting characteristic can by itself be taken as a basis for a positive comparison

False

AFIS, the automated fingerprint identification system, makes it possible to search a single latent crime scene fingerprint against an entire file's print collection

False

Because people sign their names the same way every time, if an original signature was traced over the handwriting examiner would have to conclude that the tracing was produced by the signer of the original

False

Random wear and damages to a printer impart it with class characteristics

False

Studies have recently demonstrated that common fingerprint developing agents interfere with DNA testing methods used for characterizing bloodstains, so DNA testing must precede fingerprint tests.

False

The age difference between genuine and unknown specimens is not an important factor in a handwriting comparison

False

The most common type of fingerprint pattern is the arch pattern

False

What is the third fundamental principle of fingerprints

Fingerprints have general ridge patterns that permit them to be systematically classified

List the most common feature associated with a paper examination

General appearance, color,weight, and watermarks

What was the original fingerprinting system adopted by Scotland Yard in 1901 which converted ridge patterns on all 10 fingers into a series of letters and numbers arranged in the form of a fraction

Henry system

Handwriting containing inks of different chemical compositions may be distinguished by photography with

IR light

Name 2 general categories of printers and list 2 examples of each type.

Impact and nonimpact. Thermal and dot-matrix. Inkjet and laser

What is livescan? What procedure has livescan largely replaced?

Inkless device that captures digital images of fingerprints and palm prints and electronically transmits them to an AFIS. They replaced a booking officer rolling inked fingers onto a standard ten print card for ultimate transmission to a database.

Why is it pointless to try to obscure or obliterate one's fingerprints by scarring or otherwise damaging the skin

It is totally impossible to obliterate all of the ridge characteristics on the hand, and the presence of permanent scars merely provides new characteristics for identification

What is the simplest of all fingerprint patterns, formed by ridges entering from one side of the print and exiting on the opposite side

Loop

What are the 3 types of fingerprint patterns? Which is most common?

Loops, whorls, arches. 60-65% have loops, 30-35% have whorls, 5% have arches

Name at least five factors besides handwriting characteristics that can be impart individual variations to writing

Margins, spacings, crowding, insertions, alignment, spelling, punctuation, phraseology, grammar

What 2 processes typically are involved in examination of toner

Microscopic analysis to characterize its surface morphology, and identification of the inorganic and organic components of the toner

Name 2 analytical techniques used to analyze writing inks

Microspectrophotometry and thin layer chromatography

For most fingerprint examiners, the chemical method of choice for visualizing latent prints is

Ninhydrin

What are natural variations? How can they be useful for detecting forgeries?

Normal deviations found between repeated specimens of an individual's writing. They show the examiner the range of the variations because it's a part of natural writing

Name 2 main drawbacks to using AFIS

Over reliance on a computer. Sometimes a latent print doesn't make a hit because of the poor quality of the file print. Software incompatibilities mean that state systems can't share info with each other sometimes.

What is the primary classification? What is the basis for this classification

Part of the original Henry system. Provides the first classification step in the FBI system. The presence or absence of the whorl pattern is the basis for determination of the primary classfication

Explain how latent prints can be visualized when illuminated by laser light

Perspiration contains a variety of components that fluoresce when illuminated by laser light. Fingerprints could be treated with chemicals that would induce fluorescence when exposed to laser illumination.

What is a latent fingerprint? Briefly describe how a latent fingerprint is formed

Perspiration is discharged through the pores on the skin ridges and deposited on the surface of the skin. Once the finger touches a surface, perspiration,a long with oils that may have been picked up by touching the hairy portions of the body, is transferred onto that surface. They are invisible to the eye

Name the 3 kinds of crime scene fingerprints

Plastic, latent, visible

Name 5 important characteristics of a printer, photocopier, or fax machine that a document examiner must identify when analyzing a document in a situation in which the suspect machine is not available

Printing technology, type of paper, type of toner or ink, chemical composition of toner, type of toner-to-paper fusing method

What is RUVIS and how does it work

Reflected Ultraviolet Imaging System converts ultraviolet images to locate prints on most nonabsorbent surfaces with the aid of chemical or powder treatments. Detects the print in its natural state by aiming UV light at the surface suspected of containing prints. When the UV light strikes the fingerprint the light is reflected back to the viewer, differentiating the print from its background surface. The transmitted UV light is converted into visible light by an image intensifier.

Name 2 ways in which infrared luminescence is useful in examining documents

Reveals erased writing and detect alteration of a document with ink differing from the original

How are prints from soft and porous surfaces preferably developed

Spraying ninhydrin, physical developer,

A technique for visualizing latent fingerprints on nonporous surfaces by exposing them to cyanoacrylate vapors is

Superglue fuming

What is the first thing that the criminalist must do after visualizing a print but before making any further attempts at preserving it

Take a picture

The International Association for Identification concluded that the minimum number of friction ridge characteristics which must be present in 2 impressions in order to establish positive identification is

There is no minimum order

Name 3 reasons why alternate light sources have replaced lasers for visualizing latent prints

They can give the user more flexibility in selecting the wavelength of light to be aimed at the latent print. They are cheaper than laser illuminators. They are portable and can be readily taken to any crime scene

Describe the basic process to life a fingerprint. When should this procedure be used

This should be used on large immovable objects. Fingerprint powder is applied to the print and the surface containing the print is covered with the adhesive side of the tape. When the tape is pulled up, the powder is transferred to the tape and placed on a labeled card that provides a good background contrast with the powder

What distinguishing marks serve as points of comparison on documents produced by a photocopier

Transitory defect marks from random debris on the glass platen, inner cover, or mechanical portions of a copier produce images. They form distinctive patterns and become points of comparison to link to suspect copiers. The gradual change, shift, or duplication of these marks can help date a document

A TTI, or transmitting terminal identifier, is a header at the top of each page of a fax document

True

Digital imaging has become an effective tool for enhancement and analysis of images because if the details do not exist on the original image, enhancement procedures are available to make the details clearer.

True

The individuality of a fingerprint is determined by its general shape or pattern, and it has been empirically demonstrated that no two fingerprints are alike

True

Chemical erasure of words or numbers may be revealed by an examination of handwriting under

UV light

Describe 2 methods for visualizing indented writing

When paper is studied under oblique of side lighting of applying an electrostatic charge to the surface of a polymer film that has been placed in contact with a questioned document. They can be revealed by applying toner power to the charged film.

What individual characteristics of a typewriter are valuable for proving its identity

alignments and defects on type face

What imparts individuality to a fingerprint?

identity, #, relative location of the ridge, ridge endings, enclosure, bifurification, ridge dots, ridge characteristics

A nondestructive approach to comparing ink lines is accomplished with

infrared spectroscopyluminescence

Name four common chemical methods for visualizing latent prints

iodine fuming, ninhydrin, phsyical developer, and superglue fuming

What are ridge characteristics? What is another name for ridge characteristics?

minutiae; determines fhe individuality of a fingerprint

What are fingerprints?

reproduction of friction skin ridges found on palm side of fingers and thumbs

Critical to the examination of questioned documents is

the gathering of documents of known authorship

Attempts at changing one's fingerprints by trying to obscure them has led to

the possibility of permanent scarring, which only provides new characteristics for identification because it is impossible to obliterate all ridge characteristics

The age of an ink may be determined by utilizing an ink library based on analysis by

thin-layer chromatography

Which class of fingerprints includes ridge patterns that are generally rounded or circular

whorl

What constitutional principle did the Supreme Court address in the case of US v Mara and how did it rule?

writings regarding interstate shipments; ruled that taking sample didnt constitute unreasonable search of a person and didn't violate 4th Amendment