Bloodstain science key to catching killers
Forensic scientist Mark Reynolds can tell a lot from a crime scene just by looking at the bloodstains.
"DNA and fingerprints can provide information on the identity of those involved in a serious crime such as murder, but studying the bloodstains can tell us the 'how'," he said.
Dr Reynolds, a world-renowned expert, is working with WA Police to help solve some of the State's most brutal crimes.
The former WA police officer said bloodstain pattern analysis used physics, maths, biology and chemistry to reconstruct events and could give investigators a clear understanding of what happened during a violent crime.
"It can provide indications of a person's movement through a scene, how many times a victim may have been struck, sequence-specific violent events ... and the positioning of a person at a certain time," he said.
"Quite often we can also say what didn't happen. People may have a version of events and . . . might honestly believe that's what happened, but the laws of physics are telling us that couldn't possibly have happened."
In the case of murdered millionaire Craig Puddy, killer Cameron Mansell tried to hide his crime by disposing of Mr Puddy's body and cleaning up blood inside the businessman's home.
But Mansell missed droplets of blood on the walls and ceiling.
Dr Reynolds and his police forensic colleagues were able to work out that Mr Puddy had been struck at least twice with a heavy blunt object. The first blow came as he stood near the kitchen bench. The other, after he had fallen to the floor.
Police can detect tiny drops of cleaned-up blood, bloody prints not visible to the naked eye and even stains under paint.
The police forensic team also does countless experiments in a purpose-built room with pigs' blood.
The blood room, as it is known, may look like a set from a crime show but unlike TV, investigations are rarely quick or simple. "Most people see CSI Miami or similar programs and it's done and dusted in half an hour," Dr Reynolds said.
Police might spend up to four days in a complicated bloodstain scene and walk out with several hundred exhibits, he said.
"It is painstaking and what we do then and there will dictate the value of what comes after," Dr Reynolds said.
"If we don't get it right at the time at the scene, then it doesn't matter how good the technology in the laboratory is, or how good the detectives or prosecutors are."
Dr Reynolds admits the work can be confronting and challenging, especially when children have been killed, but says it is rewarding to use science to help catch a killer or exonerate someone who is falsely accused.
