Impression Evidence Exam 2

advantages of dental stone

1. stronger

2. 2000-6000 psi

3. can be used in standing water and cold conditions

4. less expensive

why is it harder to use dental stone in snow

hardening is an exothermic reaction

materials for dental stone

plastic bag

water (4 according to kovar, 6-8 per slides ounces per lb)

form

mixing bowl and stick

steps in making a cast

1. prepare impression

2. mix dental stone

3. pour indirectly

4. let harden

5. remove the cast

how to prepare an impression

stabilize impression in certain substrates

1. for dust/dirt - spray with varnish/shellac

2. sand - spray w/ oil

3. snow - spray with snow print wax and allow to harden

how long does it take dental stone to harden

5 minutes

procedure for removing cast

1. air dry for 24-48 hours prior to packaging

2. place in a cardboard box

3. avoid airtight containers and plastic bags - cast will give off moisture

gypsum

calcium sulfate dihydrate

CaSO₄ × 2H₂O

110-130 C

plaster

calcium sulfate beta-hemihydrate

(CaSO₄)₂ x H₂O

130-200 C

Dental stone

NO WATER

calcium sulfate alpha-hemihydrate

CaSO₄

200-1000C

legal sufficiency (appellate review)

higher courts have the power to examine decisions of lower courts

Texas Rules of Evidence 702

scientific evidence must be reliable and relevant

3 criteria must be met

1. the scientific theory is valid

2. the technique is valid

3. the technique has been properly applied on the occasion being questioned

admissibility

3 stage test for the admissibility of an expert

1. must be qualified

2. subject matter of the testimony makes sense for the expert to testify

3. the expert’s testimony must assist the trier of fact to understand the evidence or decide a fact in issue

general acceptance standard

1923 - Frye v. US

the scientific technique must be generally accepted in the scientific community

Frye - wanted a “deception” test expert to testify, but it was a new technique so he was not allowed to testify

Replaced by Daubert

Weight of Evidence

allows the expert to testify and the jury gets to decide whether its good science or not

Daubert v Merrill Dow Pharmaceuticals 1973

"methodology that diverges significantly from the procedures accepted by recognized authorities in the field cannot be shown to be generally accepted as reliable”

Evidence must be relevant and reliable

The judge acts as the gatekeeper and gets to decide these things

Kumho Tire v. Carmichael

Rule 702 grants judges discretionary authority to determine reliability in light of facts and circumstances in a particular case

Exclusionary Rule

From the 4th amendment

MUST HAVE A WARRANT and must say what you’re searching for

Weeks v United States

Weeks v. United States (1914)

Weeks was doing phone scams in his house and they searched his house w/out a warrant. All evidence could not be used

Court set that the exclusionary rule applied to federal courts only

Mapp v Ohio (1961)

Exclusionary rule extended to state courts

Before this, if evidence in state courts was shown to be pertinent, it was accepted no matter what

Inevitable Discovery Doctrine

if there is a high degree of probability evidence would have been discovered by means independent of the illegal search or seizure, it is admissible

Refined in 1987 to primary and secondary evidence

Katz v United States (1967)

expectation of privacy

Exceptions to Warrant Requirement

Consent searches

plain view

abandonment

inventory search

hot pursuit

exigent circumstances

Consent Search

voluntary decision by a citizen not to assert a 4th amendment right

**very hard to determine

Plain View Doctrine

warrantless seizure of contraband or evidence of a crime where the items are in open view and the officer makes an observation from a lawful vantage point

ex.) People v Basilicato (1984) - warrant to tap phone, but picked up all conversations

ex.) traffic stop and strong weed smell, or gun on passenger seat

Inventory Search

search must be conducted according to department guidelines

can search any closed container within vehicle as long as it is allowed within department policy

Abandonment

upon abandonment, person loses all expectation of privacy

must be given up voluntarily

may not be coerced or precipitated by unlawful police activity

Hot Pursuit

suspect may not defeat an arrest by fleeing to a private place

officer may enter the premise without a warrant to search for a suspect who has fled after committing a crime under the following circumstances:

1. probable cause crime has occurred and the person being pursued committed it

2. evident person entered building when they are still in view

Permissible actions officer may take at a homicide scene

1. search for victims

2. search for perpetrator

3. seize evidence in plain view

4. secure the premises

Standing

only a person who has legitimate expectation of privacy in the area searched can claim protection of the 4th amendment

Brady v Maryland

Brady’s new attorney discovered that Boblit had given several statements admitting his guilt to police which were never brought up in court.

1. suppression by the prosecution

   1. includes the police, prosecution, and even the crime labs

2. evidence favorable to the accused

3. evidence is material