Forensic Investigation and Expert Evidence

Expert Evidence and the Coroner

This section discusses the accuracy of underlying facts in criminal accusations, categorized by types of proof:

• Absolute Proof: By itself, defines the certainty of a legal fact.
• Evidentiary Proof: The conviction that facts bring to the expert.
• Non-Evidentiary or Relative Proof: That which does not establish certainty in expert evidence, leaving only a probability.
• Refuting Evidence: Having absolute value over all other evidence, sufficient to invalidate any positive finding.

Criminalistics and Legal Medicine

Criminalistics

According to Moreno and Gonzalez, Criminalistics is the discipline that applies the methods of natural science research in the examination of sensitive material significantly related to an alleged criminal act to determine the involvement of a subject in that fact.

• Applies the deductive method (from general to particular).
• Aims to study evidence.

Key Concept: Physical Evidence

Physical or material evidence is any object, footprint, or element linked to an alleged offense, whose study allows us to reconstruct the event or identify the author and establish their participation.

Signs are based on the principle of cause and effect.

Principles Underlying Criminalistics

1. Principle of Exchange: No criminal acts without leaving usable traces behind.
2. Principle of Correspondence of Features: Two traces from the same person or two shells from the same gun will share corresponding features.
3. Principle of Reconstruction of Events or Facts: Based on evidence, reconstructs the events for explanation.
4. Principle of Probability: To deduce the probability or impossibility of a phenomenon based on the number of features examined during comparison.

Criminal Investigation

Consists of data collection and systematic analysis of the same.

Objectives at the Crime Scene

1. Perform a full reconstruction of the sequence of events, methods of operation, reason, stolen property, and anything else the offender has done.
2. Recover the traces that serve as evidence against the offender.

Investigation at the Stage of Death

• Synonyms: Lifting the corpse, scene investigation, description of the crime scene, on-site check, environment description.

Definition

The multidisciplinary work performed at the place where a corpse is found that, for judicial purposes, is conducted by the coroner and judicial investigators accompanying the trial judge or the prosecutor.