Cellphones bust the bad guys

Cellphones have become invaluable crime-fighting tools and soon could be telling detectives what a criminal had for lunch, or if he suffers from hair loss.

This has nothing to do with cellphone towers and geo-locating, but it has everything to do with the minuscule clues people leave on their phones.

Scientists from the University of California in San Diego's School of Medicine, and the Skaggs School of Pharmacy and Pharmaceutical Sciences, were able to compile what they referred to as lifestyle sketches of 39 test subjects.

"All of the chemical traces on our bodies can transfer to objects," said the lead researcher, Professor Pieter Dorrestein.

"So we realised we could probably come up with a profile of a person's lifestyle based on chemistries we can detect on objects he frequently uses."

The team swabbed four areas of the test subjects' cellphones. These were compared to swabs taken from the hands of the test subjects. They then used mass spectrometry to identify molecules in the samples.

Some of the medications detected included anti-inflammatory and anti-fungal skin creams, eye drops and anti-depressants.

Food molecules included those of citrus fruits, caffeine, and herbs and spices.

"By analysing the molecules left on their phones, we could tell if a person was most likely female, uses high-end cosmetics, dyes her hair, drinks coffee, prefers beer over wine, likes spicy food, is being treated for depression, wears sunscreen and insect spray - and therefore probably spends a lot of time outdoors - all kinds of things," said researcher Lamina Magnanimous.

"This is the kind of information that could help an investigator narrow down the search for an object's owner."

Unisa criminologist Rudolph Zinn said that the problem with this form of forensic analysis, as with all others, was controlling for contamination.

It might be good for gathering information with which to build a profile of a suspect, but detectives would still need to obtain evidence that would stand up in court.

"This trace evidence could be on the phone for a long time and could belong to someone else. But where there is trace evidence on a cellphone, there is usually DNA," Zinn said.

The researchers believe that their research could have application not only in criminal investigations but could also be useful in airport security screening, medication adherence monitoring, stratification of participants in clinical trials, and studies of the effects of environmental exposure.