Malaysian scientists have discovered an unusual but promising new tool for solving crimes: bed bugs. Long known as annoying pests that hide in mattresses and bite people at night, the insects are now proving useful to forensic investigators.
At the Science University of Malaysia (USM) in Penang, researchers have found that tropical bed bugs can store human DNA for up to 45 days after feeding. This means that if bed bugs are found at a crime scene, they could help identify a suspect who was present earlier.
Under bright lights in the USM laboratory, researchers raise colonies of bed bugs for study. The insects are kept in small containers with folded paper to mimic their natural hiding places. The room is kept at a steady temperature of 23–24°C, conditions in which bed bugs thrive.
Lead researcher Dr. Abdul Hafiz Ab Majid, an entomologist, explained that after a single feeding, bed bugs consume only a tiny amount of blood—less than one droplet. But that small amount is enough to allow scientists to recover important genetic information.
By analyzing the DNA using STR (Short Tandem Repeat) and SNP (Single Nucleotide Polymorphism) markers, scientists can determine a person’s gender, eye colour, hair colour, and skin tone, even weeks after the insect last fed.
The findings were first published in Nature’s Scientific Reports and marked the first documented forensic use of tropical bed bugs.
Dr. Hafiz said bed bugs offer several advantages over insects like mosquitoes. Once they feed, bed bugs cannot fly and rarely travel more than six metres from where they were hiding. This makes them more reliable evidence because they are likely to remain close to where the crime happened.
He also noted that bed bugs can be especially helpful at crime scenes where blood or other fluids have been cleaned up. Because they hide in cracks, seams, and soft furniture, they are often overlooked by criminals trying to destroy evidence.
In the USM lab, postdoctoral researcher Lim Li demonstrated how she allows bed bugs to feed on her arm for research purposes. She called herself a “willing victim” for science and noted that the insects are “misunderstood creatures.” She explained that bed bugs do not spread diseases, even though their bites can be itchy and uncomfortable.
Despite their potential, bed bugs are not a perfect forensic solution. Dr. Hafiz said investigators only have a 45-day window to retrieve useful DNA. And the bugs must be present at the scene in the first place.
Even so, researchers believe that bed bug DNA could one day help police solve difficult cases and identify suspects who might otherwise escape detection.
