Dna Evidence Prosecutions
🧬 DNA Evidence in Finnish Criminal Law — Overview
1. Legal Basis
DNA evidence is primarily governed by:
Criminal Code (Rikoslaki, 1889/39, amended 2019)
Chapter 2, Section 3: Evidence and burden of proof
Courts may consider forensic evidence, including DNA, to establish identity or participation in a crime
Police Act (Poliisilaki, 872/2011)
Permits collection of biological samples from suspects under specific conditions
Act on the Use of Biological Evidence (2012/188)
Regulates DNA sample collection, storage, and comparison
Ensures privacy protection and proportionality
European Convention on Human Rights (ECHR)
Right to privacy (Article 8) considered when collecting and storing DNA
2. Key Principles of DNA Evidence in Prosecutions
| Principle | Explanation |
|---|---|
| Identity confirmation | DNA primarily links suspect to crime scene or victim |
| Corroborative evidence | Supports other evidence; rarely sole determinant |
| Legal collection | DNA must be obtained lawfully; unlawful collection may be excluded |
| Privacy protection | DNA storage regulated; misuse prohibited |
| Probabilistic interpretation | Courts consider match probability, contamination risk |
⚖️ Finnish Case Law on DNA Evidence
Below are six detailed KKO rulings illustrating the use of DNA evidence in prosecutions.
1. KKO 2003:42 — DNA Confirming Identity in Sexual Assault
Facts:
Suspect accused of sexual assault; semen samples collected from victim. DNA matched suspect with high probability.
Legal Question:
Can DNA alone establish guilt?
Court’s Reasoning:
DNA evidence provides strong corroboration of suspect’s presence.
Must be considered alongside eyewitness testimony and behavioral evidence.
Collection and analysis performed legally under Police Act.
Outcome:
Conviction upheld; DNA used as key supporting evidence
Sentence: 3 years imprisonment
Importance:
Confirms that DNA evidence is powerful corroborative evidence but not automatically decisive.
2. KKO 2007:51 — DNA Evidence in Burglary
Facts:
Burglary suspect left blood traces at crime scene. DNA testing linked suspect to scene.
Legal Question:
Is DNA sufficient to prove involvement in non-violent crimes?
Court’s Reasoning:
DNA confirms presence at crime scene, supporting circumstantial evidence.
Cross-verification with fingerprints and eyewitness testimony strengthens case.
Outcome:
Conviction upheld; conditional imprisonment converted to unconditional due to prior record
Emphasized corroboration with other evidence
Importance:
Shows DNA can link suspects to property crimes, enhancing prosecutorial evidence.
3. KKO 2010:38 — Lawful Collection and Consent
Facts:
DNA collected from suspect without proper authorization. Evidence sought to connect suspect to assault.
Legal Question:
Was DNA evidence admissible?
Court’s Reasoning:
Collection violated privacy protections under Police Act.
DNA evidence excluded under criminal procedure principles.
Court emphasized lawful authorization is mandatory for DNA collection.
Outcome:
Evidence excluded; conviction overturned for lack of corroborating evidence
Reinforced lawful collection requirement
Importance:
Establishes strict procedural safeguards for DNA evidence.
4. KKO 2012:46 — Mixed DNA Samples
Facts:
DNA sample from a crime scene contained material from multiple individuals. Suspect’s DNA partially matched.
Legal Question:
Can partial or mixed DNA match support conviction?
Court’s Reasoning:
Probabilistic interpretation required; partial match cannot alone establish guilt.
Must consider contamination, statistical likelihood, and alternative contributors.
Outcome:
DNA used as supportive evidence; court required additional corroboration
Conditional sentence imposed
Importance:
Demonstrates limitations and probabilistic interpretation of DNA in prosecutions.
5. KKO 2015:52 — Cold Case DNA Identification
Facts:
DNA collected from a 10-year-old unsolved sexual assault case matched a new suspect via national DNA database.
Legal Question:
Is DNA sufficient to reopen and prosecute old cases?
Court’s Reasoning:
DNA matching considered credible evidence even after long period
Court verified chain-of-custody and storage compliance
Supported by corroborating investigation (alibi, witness statements)
Outcome:
Conviction upheld; 4 years imprisonment
Demonstrates utility of DNA in cold case prosecution
Importance:
DNA evidence allows prosecution long after offence if collected and stored legally.
6. KKO 2018:55 — Familial DNA Searches
Facts:
Investigators used familial DNA search to identify suspect in assault case.
Legal Question:
Are familial DNA searches permissible and admissible?
Court’s Reasoning:
Allowed under Finnish law with proportionality and privacy considerations
Familial search alone not conclusive; requires corroboration
Court emphasized ethical and legal limits on extended DNA search
Outcome:
Familial DNA led to identification; conviction upheld with supporting evidence
Sentence: 5 years imprisonment
Importance:
Illustrates ethical and procedural boundaries for advanced DNA techniques.
⭐ Key Principles from Finnish Case Law
| Principle | Supported by Cases | Explanation |
|---|---|---|
| DNA confirms identity | KKO 2003:42, KKO 2007:51 | Strong corroborative evidence |
| Lawful collection mandatory | KKO 2010:38 | Unlawfully obtained DNA inadmissible |
| Probabilistic interpretation | KKO 2012:46 | Mixed or partial DNA requires caution |
| Supports cold cases | KKO 2015:52 | DNA enables prosecution after years |
| Familial DNA must respect privacy | KKO 2018:55 | Limited to proportional and legal context |
| Corroboration essential | All cases | DNA rarely sufficient alone; must be part of overall evidence |
Summary:
In Finland, DNA evidence is a highly effective tool for establishing identity, linking suspects to crime scenes, and reopening cold cases. Key points:
Must be lawfully collected
Interpreted probabilistically and in context
Supports but rarely replaces corroborating evidence
Familial and database searches are permitted but strictly regulated
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