6.1 The Medicolegal Examination, Physical Evidence & the Crime Scene

Why this area matters

The 2025 Legal Medicine TOS asks you to "select the appropriate medicolegal examination for the given cases" and "explain the evidence collected from the crime scene". Every physician in the Philippines may be the first to examine an injured, assaulted or dead person, so the PLE treats this as general-practice knowledge, not specialist forensic pathology.

Who performs medicolegal examinations

A medicolegal case is any case in which a physician's findings may be used in a legal proceeding: injuries from violence, sexual assault, poisoning, suspicious or unexplained deaths, deaths in custody, and questions of identity, age or capacity. Examinations are done by:

• medico-legal officers of the Philippine National Police Forensic Group and the National Bureau of Investigation;
• municipal and city health officers;
• hospital physicians, especially in emergency rooms and Women and Children Protection Units.

For autopsy, PD 856 (the Sanitation Code) Section 95 authorizes health officers, medical officers of law-enforcement agencies and members of the medical staff of accredited hospitals.

Kinds of evidence

Locard's exchange principle: every contact leaves a trace. The suspect takes something from the scene and leaves something behind. This is why victims' fingernail scrapings, clothing and swabs are collected.

The crime scene and chain of custody

1. Protect the scene: secure the area, limit entry and record everyone who enters.
2. Document before touching anything: photographs, a sketch with measurements and written notes.
3. Collect each item separately. Dry wet biological material in air and package it in paper, not plastic, to prevent mold and DNA degradation. Label every package with the date, time, location and collector.
4. Preserve and transmit evidence with an unbroken chain of custody, meaning a written record of every person who handled it.

A broken chain weakens the evidence. In drug cases, Section 21 of RA 9165 as amended by RA 10640 sets specific inventory and witness requirements.

Examining the living

• Get informed consent from the patient, or from a parent or guardian for a minor. Explain that findings may be used in court.
• Take a history in the patient's own words, including time, place, weapon and mechanism.
• Describe each injury systematically:
  • type (abrasion, contusion, laceration, incised, stab or gunshot wound);
  • exact location measured from fixed anatomical landmarks;
  • size, shape and color;
  • features that suggest age or weapon.
• Use body diagrams and photographs with a scale.
• Estimate the healing period. This drives the Revised Penal Code classification as slight, less serious or serious physical injuries.
• Issue a medicolegal certificate limited to objective findings and opinions within your competence.

Examining the dead

• External examination: identification, clothing, postmortem changes to estimate time of death, injuries and their distribution.
• Autopsy: follows PD 856 Section 95, discussed in the death-certification section.
• Exhumation of buried remains requires legal authority, for example when a prosecutor or the Solicitor General needs to take possession of remains to determine the cause of death.

Laboratory examination of biological evidence

Motile spermatozoa may survive in the vagina for only a few hours. Nonmotile sperm are usually detectable for up to about 3 days, and longer in the cervix. Swab early, and record the interval since the alleged assault.

The Rule on DNA Evidence (A.M. No. 06-11-5-SC, 2007)

• Courts may order DNA testing on application or on their own motion when a biological sample exists, testing would yield relevant results, and the method is scientifically valid.
• In weighing the result, the court looks at:
  • how the samples were collected, handled and stored, including chain of custody;
  • the possibility of contamination;
  • the procedure and standards followed;
  • the qualifications of the analyst.
• Paternity: a probability of paternity of 99.9% or higher creates a disputable presumption of paternity. A value below 99.9% is only corroborative evidence. Results that exclude the putative father are treated in jurisprudence (Herrera v. Alba, 2005) as conclusive proof of non-paternity.
• Convicted persons may seek post-conviction DNA testing when new results could change the verdict.

The physician as witness

An ordinary witness testifies only to facts personally observed, such as "the wound measured 3 cm". An expert witness may give opinions, such as "the wound is consistent with a single-edged blade" or "the injuries will heal in 10 to 30 days", once qualified by training and experience. Under Article III of the PMA Code of Ethics, physicians must assist the government in the administration of justice, and may be fairly paid when called as expert witnesses. A subpoena from a court must be obeyed. Stay objective, testify within your competence and avoid advocacy.