A new forensic test predicts the hair and eye colour of a criminal, say scientists.
The team that developed the test said that it could provide valuable leads in cases where perpetrators cannot be identified through DNA profiling.
The Hirisplex system could allow investigators to narrow down a large group of possible suspects.
An important current approach, known as genetic profiling, involves comparing crime scene DNA with that from a suspect or with a profile stored in a database.
But this relies on the person either being among a pool of suspects identified by the police or having their profile in a DNA database.
According to Prof Manfred Kayser from Erasmus University Medical Center in Rotterdam, the Netherlands, who led the study, tools such as Hirisplex could be useful in those cases where the perpetrator is completely unknown to the authorities.
He said the test "includes the 24 currently best eye and hair colour predictive DNA markers. In its design we took care that the test can cope with the challenges of forensic DNA analysis such as low amounts of material."
"The test is very sensitive and produces complete results on even smaller DNA amounts than usually used for forensic DNA profiling," he added.
He told BBC News that the journal article described everything needed to establish the test in a forensic lab, but that the team was also in touch with industry regarding their knowledge about hair and eye colour prediction.
The test system includes the six DNA markers previously used in a test for eye colour known as Irisplex, combining them with predictive markers for hair.
In the study, the authors used Hirisplex to predict hair colour phenotypes in a sample drawn from three European populations.
On average, their prediction accuracy was 69.5 percent for blonde hair, 78.5 percent for brown, 80 percent for red and 87.5 percent for black hair colour.
Analysis on worldwide DNA samples suggested the results were similar regardless of a person's geographic ancestry.
The team was also able to determine, with a prediction accuracy of about 86 percent, whether a brown-eyed, black haired person was of non-European versus European origin (excluding some nearby areas such as the Middle East).
The findings are published in the journal Forensic Science International: Genetics.