Ch 3 notes

Essential qualities of a investigator

1. have a strong degree of self discipline 2. use legally approved methods highly ethical 3. ability to win the confidence of people whom they interact 4. do not act out of malice or bias 5. include all evidence that point to the innocense of the suspect regardless of character

The work at the crime scene is divided into 3 major functions

1. overall coordination of the scene- case agent (sr. investigator) 2. technical services- Crime lab/ CSI 3. Investigative services- interviewing, witnesses, neighborhood canvas and field interrogation of suspect, vehicle canvas

sketching usually 1-4 views

1. overhead or birds eye view (most common) 2 elevation view_ shows heights 3. cross projection view- "lays" the walls to a room down so objects of interest in the wall can be mapped 4. 3-d view- less common created with sophisticated software

Investigative process

1. to establish that a crime was actually committed 2. to identify & apprehend the suspect 3. to recover stolen property 4, To assist in the prosecution of the person charged with the crime

when investigators arrive

1st officer is responsible for briefing 2. controlling the scene 3. turning over the responsibility 4 remain @ scene until relieved

Initial response & officer safety

2. Emergency care 3. secure and control persons at the scene, boundaries of crime scene and secure it.

Visual documentation of a crime scene

3 major methods 1. Videotaping- should be done first, inexpensive, incorporated audio, use can be quickly learned 2. photographing 3. Crime scene sketching

Forensic Mapping Methods- Total station

A measuring device (inside/outside) orig (TCs, Mart) regular evidence- item does not change shape when moved, gun, knife, chair Irregular evidence- changes shape when moved- clothes

Crime Scene Sketch

A rough drawing used to document a crime scene, showing important points such as the locations where various pieces of physical evidence were located (often not to scale) Rough sketches are out in the field.

Pie/wheel search pattern

A search pattern often used at extremely large search areas that entails dividing the area into a number of pie-shaped sections, which are usually searched using the strip/line search pattern

Forensic Mapping Methods- Rectangular coordinates

Best w/ scenes clearly specific boundaries

Associative Evidence

Bidirectional evidence that connects the perpetrator to the scene or victim, or connects the scene or victim to the perpetrator.

Forensic Mapping Methods

Choice of method influenced by factors: size of scene of personnel available, weather, obstruction

types of evidence

Each criminal offense contains a distinct set of elements whose commission or omission must be demonstrated to have occurred in order to prove a case.

Tracing Evidence

Evidence that helps identify and locate the suspect.

deductive reasoning

Hypothesis about the crime. the explanation is tested against the factual situation. if the fit is good.

Crime scene safety concerns

Infections diseases- wear latex gloves when contact w/blood, bodily fluids, body parts, weeping lesions, body membranes or non-intact skin of others is possible- Do not touch handle petroleum products when wearing latex gloves 2 degradation "eat through" wear vinyl instead nitrile gloves if latex sensitivity

Forensic Mapping Methods- Triangulation

Interior scenes in bldings, outdoor where measurements spring from distinct perm. features

The most important skill of an investigator?

Is the ability to converse equally well with a wide range of people.

Inner perimeter

Protects and contains the immediate scene through which no one passes except those recognized as being essential.

suspended searches, debriefing and release of scene

Search should not be terminated until all possible fruitful avenues for developing physical evidence have been thoroughly explored -photograph scene again before releasing it to counter any false claims of property damage

2 common reasons for states refusing to extradite:

Suspect already incarcerated on a serious charge or suspect. 2. Will be tried on a more serious charge

outer perimeter

The area that encircles the inner perimeter at a safe distance from the incident scene. The outer perimeter protects entrance and exit routes to the inner perimeter to ensure free movement of essential services and equipment.

Types of crime scenes-Primary scene

The location where the initial offense was committed. location of all subsequent connected events

Hepatitis C (HCV)

The most widespread chronic blood-bourne illness in the US. No Vaccine available. TB Chronic bacterial infection spread by air.

Fundamental rules must be observed- Apply inclussiveness

The of inclusiveness dictates that every available piece of evidence be obtained of where there is a question as to whether a particular item constitutes evidence be defined as such. the rational is that mistakes made in the excluding potential evidence often cannot be rectified rule also requires- standard samples and elimination prints always be obtained when appropriate

Cleared by arrest

The perpetrator has been arrested and there is sufficient evidence to file criminal charges (this definition does not require a conviction)

forensic mapping

The process of taking and recording the precise measurements of items of evidence to be drawn or "fixed" on the sketch

There can be no crime

Unless there is advanced notice that the conduct is prohibited or required

Search Patterns- Spiral

Usually outdoor scenes executed by 1 person

trace evidence

often located using alternative light systems (ALS)- Portable lasers, such as polilight blue maxx- and luma lite and handheld UV lighting- a light sweeps cause evidence to fluoresce. Includes: fingerprints bodily fluids hairs, fibers, drugs, glass metal, bite marks, bruises, human bone and gunshot residues.

Forensic Mapping Methods- Polar coordinates

outdoor for large area

Forensic Mapping Methods- Grid system

outdoor large area w/ no sig. land marks

Follow up investigation

the effort expended by the police gathering information during the period between the initiation of the original report and the time the case is ready for prosecution or closed.

crime scene reconstruction

a hypothesis of the sequence of events from before the crime was committed through its commission

Strip/line search pattern

a search pattern often used outside by several people in which the search area is divided into lanes that are searched by one or more people in both directions until the entire area has been examined.

Grid Search

a variation of the strip/line search pattern. It overlaps a series of lanes in a cross pattern.

Microscopic scenes

consist of specific objects and pieces of evidence associated w/ commission of the crime- including knives, bite marks, hairs, fibers

corpus delicti evidence

establishes that a crime was committed

maintain documentation

from initial notes to all logs and reports

Fundamental rules must be observed- Proceed with Caution

in approaching the point of fucus, small but extremely important evidence may be altered or destroyed arent to be searched my be too rapidly defined and other areas that might be fruitfully explored are overlooked or given only a cursory examination

General rule

it is better to establish the perimeters more broadly

Types of crime scenes- Secondary scene

location of all subsequent connected events

Hepatitis B

most common serious disease in the world, leading cause of cancer and liver failure. - officers would contract HBV in the same way they would HIV exposure to blood and bodily fluids. more potent then HIV

inductive reasoning

moves from specific to general

In defining the scene

officers must make sure they also id possible or actual lines of approach to the if flight from the scene and protect them

exceptionally cleared

police an demonstrate who committed the crime, but for any of several reasons, cannot pursue the case further ex: suspect is dead, witness refuse to testify.

Investigator

someone who gathers, documents, and evaluates evidence and information

preliminary investigation

the actions taken by the first officer to arrive at the scene of the crime after its detection and reporting. (usually a uniformed patrol officer)

Zone/quadrant search pattern

used for vehicle searches, outdoors, or a large area. Divide the area into four different sections and search each using one of the patterns above.

Fundamental rules must be observed- maintain control

Crowds/ media

Fundamental rules must be observed- Conceptualize events

How the crime was committed- assumptons made must be checked for accuracy ASAP

Marcroscopic scenes

Large view" includes such things as the relevant locations, victims and suspects bodies, cars, buildings

Evidence procedures

Maintain chain of custody- document who had the evidence

Forensic Mapping Methods- Baseline coordinates

Similar to rectangle inside/outside

Boundary determination

(of a crime scene) Inner and outer perimeters

BOLO- what to include

1. # of suspects, age. race, sex, ht, wt, build, scars, clothing, weapons, vehicle, damages and want

3 types of crime scene reconstruction

1. accident or transportation oriented recon 2. specific crime recon 3. shooting recon

Successful investigators

1. good communication skills 2. strong ethics 3. initiative 4. resourcefulness 5. compassion * investigators must ensure that crimes are investigated effectively and thoroughly. complete preliminary and follow up. investigations also understanding the importance of physical evidence in a criminal investigation.