The FBI has developed sophisticated new software for reconstructing a person's face from their skull. The software is designed to help police identify partially decomposed or burned bodies.

At present, reconstructing a face from a skull takes a specialist artist up to two weeks and can cost up to $2,000 (£1,020).

"Often described as a blending of art and science, these methods require a skilled artist and are labour-intensive and therefore expensive," wrote Diana Moyers, of the University of Tennessee, Knoxville, in the Proceedings of the American Academy of Forensic Sciences annual meeting in Washington.

"Traditional methods do not effectively address decomposing remains or situations with a large number of remains, such as mass disasters and genocides."

The FBI's ReFace (Reality Enhancement Facial Approximation by Computational Estimation) system uses a library of CT scans of living individuals' faces to make facial reconstructions. It was developed for the FBI by General Electric Global Research and is undergoing validation and testing at the FBI's counterterrorism and forensic science research unit in Quantico, Virginia.

Moyers was brought in by the FBI to find out how accurate the software is. "We knew that it makes faces, but do they look like the person?" she said.

Moyers gave the system 10 skulls of six women and four men from her university's forensic skeletal collection. She then asked 103 volunteers to match the facial reconstructions from the software to actual photographs of the people. For all but one of the skulls the volunteers did better than chance in their guesses. The system looked promising as a replacement for the laborious process of artistic reconstruction.

Her colleague Dr Murray Marks, also at the University of Tennessee, tested how good a prototype face recognition system - which is used for matching images of people on CCTV to photographs - was at doing essentially the same task as the human volunteers. Again, the face recognition software performed better than chance.

An estimated 40,000 sets of unidentified human remains are held by medical examiners, coroners and forensic anthropologists in the US, according to Marks.

"Clearly there is an urgent need to be able to systematically and correctly process large numbers of victims in a cost-efficient and expeditious manner," he wrote.