Pets are not usually the first thing investigators think about when examining a crime scene.

But new Australian research suggests dogs and cats may hold valuable forensic clues, especially in cases where human DNA transfer is being examined.
Research from Flinders University, Victoria Police Forensic Services Department and Forensic Science South Australia has looked at how household pets can act as intermediaries in human DNA transfer. The research highlights that pets may carry DNA from people they have come into contact with, and may also move that DNA to other surfaces or locations.

Why this matters for forensic investigations
In many homes, pets move freely between people, rooms and surfaces.
They may be touched by owners, visitors, family members or people of interest. They may also brush against furniture, flooring, clothing or objects within the home.
This creates a new area for forensic teams to consider.
The research found that even short contact between people and pets can leave detectable human DNA on dogs and cats. It also found that pets may carry and transfer DNA as they move through a home or to other locations.
For investigators, this could offer another possible avenue for DNA leads in serious criminal cases.

Pets as possible DNA carriers
The idea is not that pets are evidence in the same way as a weapon, fibre or bloodstain.
Instead, pets may act as carriers of human DNA.
For example, if a person touches a dog or cat, their DNA may remain on the animal’s fur. That DNA may later be transferred to another person, surface or location.
This could help investigators understand who may have interacted with a pet, or how DNA may have moved around a scene.
However, it also creates an important caution. DNA found at a scene does not always mean a person was physically present at that exact location. DNA can move indirectly through people, objects, clothing, surfaces and potentially animals.
That is why DNA evidence must always be interpreted carefully and in context.

A new consideration at residential crime scenes
This research is especially relevant to residential crime scenes.
Many households have pets, and they are often present during everyday interactions. In some cases, they may also be present before, during or after a criminal event.
Flinders University researchers note that dogs and cats have often been overlooked in forensic casework, but their presence may be important when considering DNA transfer and contamination pathways.
This does not mean pets should be sampled in every case.
It means investigators may need to ask an extra question when assessing a scene:
Could a pet have played a role in transferring DNA?

Supporting better evidence interpretation
The value of this research is not only in finding new DNA leads. It also helps forensic teams better understand how DNA can move.
This matters because DNA evidence is powerful, but it is not always simple. A DNA profile may help link a person to a scene, object or interaction, but the way that DNA arrived there still needs careful interpretation.
If pets can carry and transfer human DNA, forensic teams may need to consider them when reconstructing movements, contact and possible contamination.
This could be especially important in homes, vehicles, shared spaces or cases where animals are known to be present.

What this means for investigation teams
For law enforcement, forensic laboratories and crime scene teams, this research reinforces the importance of proper evidence collection and documentation.
When pets are present at a crime scene, teams may need to record their presence, movement and possible contact with people or surfaces.
As forensic science continues to develop, the focus is not only on collecting more evidence. It is about collecting the right evidence and understanding what it means.
Small details at a scene can sometimes make a significant difference.
In this case, even a household pet may help investigators piece together part of the story.

Supporting modern forensic workflows
RollsTech Global works with forensic, law enforcement and government teams across Australia and New Zealand, providing forensic consumables, evidence handling products, crime scene equipment and investigation workflow solutions.
From swabs and evidence bags to forensic technology and chain of custody systems, RTG supports teams in collecting, protecting and managing evidence with care.
Contact our team to learn more about forensic consumables and evidence handling solutions for modern investigations.

Reference: Flinders University News, Silent witnesses: Pets offer a fur-ensic tale