Fporensic

Forensic science

The application of science to criminal matters (to the law).

Crime Scene Investigator (CSI)

Usually police, trained to recognize, protect, collect, document evidence, and maintain chain of custody.

Forensic Scientist (FS)

Civilian with scientific education, spends 50% of time in lab and 50% testifying in court.

Scientific Method

formulate a question worthy of investigation.

Objective in Scientific Method

Who killed the wife?

Hypothesis in Scientific Method

Is the husband guilty?

Methodology in Scientific Method

Evidence processing.

Results in Scientific Method

Data.

Conclusion in Scientific Method

Who is guilty? (Arrest, Court, Conviction)

Scientific Measurements

Quantitative data that has some uncertainty (errors).

Gross error

Human error.

Systematic error

Equipment error, calibration.

Random error

Fluke of nature, no pattern.

Preliminary scene examination

Further secure scene (after 1st responder) and look for modus operandi (MO) to identify a serial crime.

Types of systematic searches

Spiral search, Line search, Grid search, Zone search.

Documentation of a crime scene

Recording crime scene through sketching, measurements, and photographs.

Chain of custody

written passage of evidence

Crime scene reconstruction

Collecting and preserving evidence to piece together the crime scene.

Compound microscope

Magnification power of x450; visual image is inverted.

Comparison microscope

Side by side comparison of samples (e.g., bullets, fingerprints, blood samples).

Polarizing microscope

the ability to refract light into two different directions to reveal crystal structures, mineral.

Stereomicroscope

Space between the stage and objective lens is biggerr. visual image is upright.

Microspectrophotometer

measures the intensity of wavelengths in a light spectrum

Scanning electron microscope (S.E.M.)

Visual image is formed by a beam of electron emission; high magnification (10-100,000x resolution).

Evidence

Anything that tends to prove or disprove something at issue; must be relevant and probative.

Physical evidence

objects/things

Nonphysical evidence

Verbal testimony and actions during a crime.

Real evidence

Generated by the crime and found at the crime scene.

Demonstrative evidence

Created to help explain or clarify real evidence; not produced by crime.

Known evidence

Materials whose source/ownership is known at the time of collection.

Unknown evidence

Materials found at the crime scene without a known origin.

Class evidence

a piece of evidence that arises only from several sources.

Individual evidence

a piece of evidence that arises only from one source.

Coroner

Duty is to officially investigate death

Medical examiner

Appointed official responsible for certifying manner and cause of death

Primary cause of death

Immediate cause of death

Secondary cause of death

Contributing causes to the primary cause of death

Manners of death

homicide, suicide, accidental, undetermined.

Homicide

Death caused by another person

Natural causes

Death due to natural biological processes

Accidental

Death resulting from unintended incidents

Suicide

Death caused by self-inflicted harm

Undetermined

Circumstances of death cannot be conclusively determined

Autopsy

Examination of a body to determine cause of death

External autopsy

Carried out upon discovery of a corpse to check for visible signs of injury

Internal autopsy

Examination that starts with a Y-shaped incision to expose internal organs

Mechanical causes of death

Examples include gun shots, forced trauma, stabbing, motor vehicle incidents

Chemical causes of death

Examples include drugs, alcohol, poisons

Electrical causes of death

Examples include electrical voltage

Thermal causes of death

Examples include burns or extreme cold

Postmortem Interval (P.M.I.)

Time elapsed since death

Algor mortis

Tendency of body to cool after death

Rigor mortis

Degree of stiffening of the body after death

Livor mortis

Blood pooling at the lowest part of the body under gravity

Embalming

Injecting the body with formaldehyde to halt the decomposition process

Forensic anthropology

Applying osteology to matters involving the law

Human skeleton

Adults have 206 bones; infants have 231 bones

Functions of bones

Support, protect vital organs, body's site for growth

Identification of skeletal remains

Presence of haversian canals indicates specimen is bone

Biological profile

Determining age and gender from skeletal remains

Fingerprint classification

Includes latent, patent, and plastic fingerprints

latent

invisible

patent

visible

plastic

three-dimensional