Pets, "Silent Witnesses" in Criminal Investigations

A recent Australian study shows that pets, such as dogs and cats, may play an unexpected role in solving crimes, as they can carry and transfer human DNA between people and places. The discovery offers forensic investigators a new perspective on how to interpret genetic evidence found at a crime scene, Xinhua reported. The research, conducted by Flinders University in Australia in collaboration with police experts from the state of Victoria, analyzed how domestic animals can function as intermediaries in the indirect transfer of DNA. According to the results, dogs and cats - present in many households and in frequent contact with several people - can retain detectable human DNA on their fur even after brief interactions. This phenomenon could help investigators identify links between suspects and the scene of a crime. "Dogs and cats are present in most households and interact constantly with people and different environments,” explained Heidi Monkman, a PhD student in Flinders University's Faculty of Science and Engineering and the lead author of the research.

• Indirect DNA transfer between people and places

The studies were conducted through controlled interactions between animals and volunteers, to observe how DNA is transferred. The results showed that:

A person's DNA can remain on the animal even after brief contact;

The owner's DNA can be indirectly transferred to other people; and genetic traces can reach places where the owners have never been. These mechanisms can help reconstruct a person's route in a criminal investigation, but they can also generate the risk of misinterpretation of evidence if indirect transfer is not taken into account. According to the researchers, awareness of this phenomenon can become extremely useful in serious cases, because animals can function as "vectors” of DNA transfer. "We are exploring the potential of dogs and cats to act as silent witnesses and as vectors of contamination and transfer at crime scenes,” said Heidi Monkman. Experts say the results could lead to updated forensic procedures, by including pets in the analysis of genetic evidence when they are present at a crime scene.

• A useful tool, but one that requires caution

Specialists point out that indirect DNA transfer is a complex phenomenon, and the interpretation of evidence must be done with caution, to avoid erroneous conclusions. However, the discovery opens a new direction in forensic investigations, demonstrating that domestic animals can become valuable sources of information in establishing the circumstances of a crime.