IMPRESSION EVIDENCE

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IMPRESSION EVIDENCE
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MARIA RICHARDSON CASE

• Charlie Richardson 30-year old student
  completing his final year in medical school
• VICTIM Maria Richardson, defendants wife of
  several years

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Case (cont.)

• On the morning of December 30, 1998, the
  defendant drove Maria to her workplace, a lab in
  El Cajon, CA.
• An argument ensued and Charlie strangled Maria
  with a ligature.
• After killing her, he scattered and misplaced
  laboratory specimens and the contents of Marias
  purse to make it appear like a burglary.
• Charlie then drove to the Univ. of CA, San Diego,
  medical school library to study for an exam.

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Case (cont.)

• Later the in the morning, a co-worker found
  Marias body in the laboratory.

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Case (cont.)
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Case (cont.)

• Charlie was asked for background information
  about Maria.
• He related his actions of the morning, explaining
  how he left his wife at work, and then went to
  the library to study. He had planned to meet
  Maria fo rlunch and produced time-stamped
  receipts from various locations.

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Case (cont.)

• The victim had ligature
• marks on her neck and
• chin.

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Case (cont.)

• Several items that could have been used as a
  ligature were collected, including a long
  telephone cord that was attached to a wall phone.
  
• During the investigation, a small crescent-shaped
  abrasion was noted on the edge of Charlies right
  pinky finger.

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Case (cont.)
Abrasion on right pinky finger, which defendant
explained was due to a burn received while he
was Cooking.
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Case (cont.)

• He was unable to explain a very small, less
  visible matching abrasion along the edge of the
  left pinky finger.
• Charlie was arrested for the murder of his wife
  Maria.
• Dr. Norman D. Skip Sperber, a forensic
  odontologist, was called into the investigation.
• He made castings and took photographs of the
  suspects fingers and of the ligature marks on
  the victims neck.

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Case (cont.)
Dr, Sperber making castings of the defendants
left and right pinkies.
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Case (cont.)
Telephone cord fitted into casting of the
ligature mark on the victims neck.
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Case (cont.)
The telephone cord fitted into a casting of one
of the defendants pinkies.
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Case (cont.)

• A continued investigation yielded evidence of
  marital disharmony.
• Writings of Maria were found stating that she was
  afraid of Charlie.
• The defense offered to plead to a charge of
  involuntary manslaughter on condition that
  Charlie would take the stand and tell the jury
  what actually happened.

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Case (cont.)
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Case (cont.)
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Case (cont.)
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Case (cont.)

• The defendant took the witness stand and told how
  he strangled Maria with the telephone cord during
  the course of a heated argument.

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Impressions
A four week old infant was bitten by the family
pet.
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Impressions (cont.)
The Great Danes teeth were compared with a cast
of the wound.
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Impressions (cont.)
Cast of the wound.
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Footprints

• Footprints are a common type of impression
  evidence found at or near crime scenes.
• In favorable situations, such evidence may
  conclusively demonstrate that the suspect was at
  the scene of the crime.

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Footprints (cont.)

• A detailed examination of footprints is tedious
  and time-consuming work, and as a result, may be
  overlooked by the investigator.
• The investigator should not overlook soil
  evidence that might later be discovered on the
  suspects shoes.

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Footprints (cont.)

• The result of casting on soft ground the cast
  has an arched form.
• The back of the heel and the point of the toe are
  considerably lower than the other parts of the
  cast.
• Due to normal walking motion heavier pressure on
  heel and toe.

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Footprints (cont.)

• When running, the footprints are less distinct,
  partly owing to the slipping of the foot and
  partly to sand and earth being thrown into the
  print.
• In deciding whether an individual walked or ran,
  there is only one certain guide the length of
  the step.

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Footprints (cont.)

• A footwear print maybe a foot impression or a
  footprint (dust print).
• Foot impressions occur when foot treads on some
  moldable material such as earth, sand, clay,
  snow, etc.
• Footprints are formed on a hard base when the
  shoe is contaminated by dirt, dust, flour, blood
  or moisture.

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Preservation of Footwear and Tire Impressions

• Generally formed outdoors
• Precautionary measures protect by covering with
  a box or by cordoning off the area.
• Impressions in snow should be protected by a box
  covered with snow to prevent thawing.

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Preservation of Footwear Evidence

• Photographing
• Casting

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Preservation (cont.)
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Preservation (cont.)

• Lifting of dust prints

An electrostatic dust print lifter
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Preservation (cont.)
A photograph of a luminol rxn in a double
homicide in Nome, Alaska
Test shoe impressions of the suspect
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Casting

• Any material that may have fallen into the
  impression after it was formed should be cleaned
  away.
• If it is not possible to carry out this cleaning
  without injuring details of the impression, it
  should be omitted.
• Materials trampled into the impression, such as
  leaves or grass, should not be removed, as they
  actually form part of the impression.

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Casting (cont.)

• Any water present should be carefully removed by
  a hypodermic syringe or small pump.
• Casting is generally done with dental stone.
• Other materials include plaster of paris,
  paraffin, sulfur and silicone rubber, but are
  less frequently used.

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Casting (cont.)

• A retaining wall or frame should be placed around
  the impression.
• The cast should be at least two inches thick.
• After the material is mixed, it should be gently
  poured onto an area adjacent to the impression
  and allowed to flow onto the impression.
• If it is necessary to pour directly into the
  impression, a baffle such as a flat stick or
  spoon can be used to lessen the impact.

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Casting (cont.)

• Before the cast hardens, it should be marked by
  means of a twig or other sharp instrument.
• The information should include
• The cast date
• Investigators name or initials
• Case number
• Location of impression

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Casting (cont.)

• The material will harden sufficiently for removal
  in about 30 minutes.
• Clumps of soil and rocks clinging to the cast
  should not be disturbed.
• Cast should be allowed to air dry for about 48
  hours.