In an effort to stop their defendant from being sentenced to death, attorneys for convicted murderer John Couey are using brain scans to try and explain why he abducted and murdered 9-year-old Jessica Lunsford.
Turning to science, Couey's attorneys are arguing that his brain is abnormal; they are comparing Couey's brain to a normal one. They say his brain's abnormality caused him to suffer from uncontrolled sexual urges and aggression.
Lawyers have been using neuroscience since the 1990s to explain behavior, but legal experts say that understanding why someone did something is different from excusing the action. That difference will be the basis for the jury's decision in this case.
The jury heard emotional testimony from friends and neighbors of Jessica's family; their lives were ripped apart by the crime.
Jessica was abducted from her Florida bedroom, raped, murdered and buried in plastic bags, which were later found outside a trailer where Couey had been living.
Last week, he was convicted of murder.
Now the question is whether Couey should be put to death and whether he knew what he was doing.
In the courtroom, Couey drew pictures as his life hanged in the balance.
"The only shot they have [is] if the defense put his brain on trial," said Kendall Coffey, the former U.S. attorney for south Florida.
The defense wants to show that the scan is a road map to his dark reality and that he committed these heinous crimes because of his brain. Experts say while brain scans may be useful, the science -- unlike DNA or fingerprint evidence -- is still new.
"Neurobiology doesn't yet support being able to make precise inferences from a scan of somebody's responsibility," said Art Caplan, a bioethicist at the University of Pennsylvania.
Coffey said he believed that if Couey's defense team was successful it could start a trend of using brain scans as evidence.
"If John Couey, given the horrible nature of this crime, doesn't get the death penalty because of brain scans, then you're gonna be seeing a lot of brain scans and a whole lot of mental impairment discussions in every capital case from now on," he said.
In sentencing, some think this kind of evidence is proving more and more persuasive with juries and is starting to change how they look at sanity.