The Angry Exile: DNA evidence = 'Do Not Assume' evidence.

The Hangman

Into our town the Hangman came,
Smelling of gold and blood and flame.
And he paced our bricks with a diffident air,
And built his frame in the courthouse square.
The scaffold stood by the courthouse side,
Only as wide as the door was wide;
A frame as tall, or little more,
Than the capping sill of the courthouse door.
And we wondered, whenever we had the time,
Who the criminal, what the crime
That the Hangman judged with the yellow twist
of knotted hemp in his busy fist.
And innocent though we were, with dread,
We passed those eyes of buckshot lead --
Till one cried: "Hangman, who is he
For whom you raised the gallows-tree?"
Then a twinkle grew in the buckshot eye,
And he gave us a riddle instead of reply:
"He who serves me best," said he,
"Shall earn the rope of the gallows-tree."
And he stepped down, and laid his hand
On a man who came from another land.
And we breathed again, for another's grief
At the Hangman's hand was our relief
And the gallows-frame on the courthouse lawn
By tomorrow's sun would be struck and gone.
So we gave him way, and no one spoke,
Out of respect for his Hangman's cloak.
The next day's sun looked mildly down
On roof and street in our quiet town,
And stark and black in the morning air
Was the gallows-tree in the courthouse square.
And the Hangman stood at his usual stand
With the yellow hemp in his busy hand;
With his buckshot eye and his jaw like a pike
And his air so knowing and business-like.
And we cried, "Hangman, have you not done
Yesterday, with the foreign one?"
Then we fell silent, and stood amazed,
"Oh, not for him was the gallows raised."
He laughed a laugh as he looked at us:
"Did you think I'd gone to all this fuss
To hang one man? That's a thing I do
To stretch a rope when the rope is new."
Then one cried "Murder!" and one cried "Shame!"
And into our midst the Hangman came
To that man's place. "Do you hold," said he,
"with him that was meant for the gallows-tree?"
And he laid his hand on that one's arm.
And we shrank back in quick alarm!
And we gave him way, and no one spoke
Out of fear of his Hangman's cloak.
That night we saw with dread surprise
The Hangman's scaffold had grown in size.
Fed by the blood beneath the chute,
The gallows-tree had taken root;
Now as wide, or a little more,
Than the steps that led to the courthouse door,
As tall as the writing, or nearly as tall,
Halfway up on the courthouse wall.
The third he took -- we had all heard tell --
Was a usurer, and an infidel.
"What," said the Hangman "have you to do
With the gallows-bound, and he a Jew?"
And we cried out, "Is this one he
Who has served you well and faithfully?"
The Hangman smiled: "It's a clever scheme
to try the strength of the gallows-beam."
The fourth man's dark, accusing song
Had scratched our comfort hard and long;
"And what concern," he gave us back.
"Have you for the doomed -- the doomed and Black?"
The fifth. The sixth. And we cried again,
"Hangman, Hangman, is this the man?"
"It's a trick," he said. "that we hangmen know
For easing the trap when the trap springs slow."
And so we ceased, and asked no more,
As the Hangman tallied his bloody score.
And sun by sun, and night by night,
The gallows grew to monstrous height.
The wings of the scaffold opened wide
Till they covered the square from side to side;
And the monster cross-beam, looking down,
Cast its shadow across the town.
Then through the town the Hangman came,
Through the empty streets, and called my name --
And I looked at the gallows soaring tall,
And thought, "There is no one left at all
For hanging, and so he calls to me
To help pull down the gallows-tree."
So I went out with right good hope
To the Hangman's tree and the Hangman's rope.
He smiled at me as I came down
To the courthouse square through the silent town.
And supple and stretched in his busy hand
Was the yellow twist of the hempen strand.
And he whistled his tune as he tried the trap,
And it sprang down with a ready snap --
And then with a smile of awful command
He laid his hand upon my hand.
"You tricked me. Hangman!," I shouted then,
"That your scaffold was built for other men...
And I no henchman of yours," I cried,
"You lied to me, Hangman. Foully lied!"
Then a twinkle grew in the buckshot eye,
"Lied to you? Tricked you?" he said. "Not I.
For I answered straight and I told you true --
The scaffold was raised for none but you.
For who has served me more faithfully
Then you with your coward's hope?" said he,
"And where are the others who might have stood
Side by your side in the common good?"
"Dead," I whispered. And amiably
"Murdered," the Hangman corrected me:
"First the foreigner, then the Jew...
I did no more than you let me do."
Beneath the beam that blocked the sky
None had stood so alone as I.
The Hangman noosed me, and no voice there
Cried "Stop!" for me in the empty square.

Maurice Ogden

Saturday 8 May 2010

DNA evidence = 'Do Not Assume' evidence.

Millions to one against, that's what they used to say about the reliability of DNA evidence. Soon it became billions to one, and now juries around the world are given the impression, perhaps aided by TV, that DNA evidence is a magical standard on a par with several dozen eye-witnesses and a signed confession. So much faith is put in it that people will even say that murderers convicted on DNA evidence may as well be executed since no doubt exists.

Maybe.

DNA evidence has certainly caught and convicted criminals, though much of the time it's part of a variety of evidence and fairly few cases rest solely on DNA. But does that mean 100% reliability? It'd be convenient to think so but unfortunately DNA evidence is far from perfect. 22 year old Farah Jama can tell you that.

"Nobody will understand the pain I went through … or the stress," Mr Jama said. "You kind of lose hope."

What he refers to is spending fifteen months in jail for a rape which he did not commit. A rape that he was found guilty of because DNA evidence, despite a "mountain of improbabilities", is considered nigh on infallible. And it might be close to infallible when done right, but human beings are not infallible and the gathering of DNA evidence is carried out by human beings. Now and again they will stuff things up.

Mr Jama was found guilty of raping a 40-year-old woman at a nightclub in Melbourne's outer-eastern suburbs after the victim was found unconscious.

She had no memory of the crime but Mr Jama's DNA was later found on the victim.

The then 20-year-old denied ever being near the nightclub on that night, saying he was reading the Koran to his critically ill father at his bedside in their home in the northern suburbs.

The only evidence police had was the DNA sample of Mr Jama, which was coincidently taken 24 hours before the alleged crime after he was investigated over another unrelated matter but not charged.

Prosecutors told the court this morning that it had since been discovered that the same forensic medical officer who took the first DNA sample of Mr Jama had coincidently taken the DNA sample from the 40-year-old rape complainant 24 hours later.

It turned out that that medical officer did not follow protocols designed to prevent contamination of samples, and this hugely important point was not considered.

The report by former Supreme Court judge Frank Vincent - tabled in Parliament yesterday - slammed Victoria Police, the Office of Public Prosecutions, and forensic medical officers over the case and the authorities' failure to consider any other evidence connecting Mr Jama to a crime that never occurred.

...

Last December, Chief Commissioner Simon Overland banned police scientists from giving evidence in court until further notice after it was discovered that statistical analysis used to interpret DNA tests had not kept pace with new-generation DNA equipment.

The ban came days after Mr Jama's rape conviction was overturned because of contaminated DNA evidence, and lasted until January 12.

In his report on Farah Jama, Mr Vincent said: "The DNA evidence appears to have been viewed as possessing an almost mystical infallibility. The outcome was, in the circumstances, patently absurd," he reported.

"There were ample warning signs … but they were simply not read."

Consider the possibilities if the same thing happened in a murder case somewhere that still uses capital punishment. Except for the most obvious way of leaving getting off Death Row is probably tricky once you're on it. But even in non-death penalty convictions placing such faith in DNA that innocents are sent to jail is both costly, unjust and, given that the police stop looking for an offender, inefficient - a true lose-lose situation.

Nor is cross contamination the only potential pitfall, as pointed out here. You shed your DNA when you walk across the room so any DNA found at a crime scene is often circumstantial, it degrades meaning potentially coincidental partial matches may result, and despite the overwhelming odds quoted it's impossible to rule out a coincidence - a million to one means 20 other matches to my DNA just here in Australia alone, and even a billion to one would mean five or six other people worldwide.

So is it unreliable? No, quite the reverse. But mistakes are made and they're not being caught in time to prevent miscarriages of justice. This almost unshakeable faith in the reliability of DNA matches badly needs to be shaken.