Serology: It's in the Blood
Analysis Gone Wrong
It should be kept in mind that analysis always involves interpretation. In the case below, an interpretation of the bloodstain evidence helped to convict a woman and stood up to two appeals, but turned out to have been in error.
In Australia in 1980, Lindy and Michael Chamberlain took their three children camping near Ayers Rock. The youngest was nine-week-old Azaria.
One evening, according to Lindy and Michael, they were preparing dinner at the camp barbecue site when they heard a sudden sharp cry from the tent in which Azaria was sleeping. Lindy went to check and saw a dingo, or wild dog, backing out, shaking something large in its jaws. It ran away and that's when Lindy discovered that Azaria was gone. The dog had taken her!
Trackers searched the area to no avail. There was no sign of the missing baby or the dingo, except for footprints leading to the road and beyond. The parents grieved deeply, but eventually accepted their fate as the will of God. They assumed she was dead.
Eight days later a hiker discovered baby Azaria's clothing in a crumpled heap west of Ayer's Rock. Only the baby's jacket was missing, but oddly, her undershirt was inside out and the booties were neatly laced up inside the jumpsuit. On the neck of the jumpsuit and undershirt were bloodstains that were later thought to be consistent with the type of stain that would result from a knife cut, not a bite. There were also no tooth marks on the clothing.
Around the scene, investigators found no sign of human remains, no dog hair, and no indication that violence had occurred between an animal and a baby. No dingo saliva was found on the clothing. Investigators did some experiments with caged dingoes and concluded that whatever had happened to the child had not involved a wild dog. That left human involvement — someone who left the child's clothing several miles from where she was taken. Suspicion turned to the parents, and then more specifically to Lindy.
Lest there was doubt about whether the clothing belonged to the child, blood tests were done to determine type (no DNA testing was available then), and then compared to the Chamberlain's blood types. The conclusion was that the clothing had belonged to Azaria. Another test showed that the undershirt had been worn the right way when the wound was made, but then someone had removed it, leaving it inside out. There also appeared to be two bloodstained prints on the jumpsuit made by the hands of a small adult, like a woman.
A search of the Chamberlain's car produced what appeared to be the blood of an infant on the seats and on a pair of scissors in the vehicle. After that, the Chamberlains were arrested and tried for the murder of their baby daughter. They insisted they were innocent, but the evidence appeared to say otherwise. Lindy was convicted of murder and Michael was declared an accessory to the crime. Lindy went to prison.
On her behalf, many people began movements to bring out the errors made in the interpretation of evidence — particularly the experiments done with dingoes and the blood analysis. The substance found in the car, for example, was not conclusively proven by any tests to be blood. Nor was the stain on the T-shirt proven to be from a cut rather than from an arterial bleed. If the dingo had grabbed the baby by the head or neck, there would be no teeth marks on the clothing.
Then in 1986, four years after the trial, Azaria's missing jacket was finally located — partly buried in sand near a dingo cave not far from the campsite. It was torn and bloodstained, but in good enough condition to be identified as the one Azaria wore the last time she was seen. It was sufficient for reasonable doubt and Lindy was released. The following year, the couple was officially pardoned. Not long afterward, their convictions were quashed.
No matter how sophisticated the tests, interpretation is often subject to the narrative that the investigators build, especially if the evidence is ambiguous. It can only be hoped that future technology will eliminate the gray areas and provide more conclusive proof.