“Think about what you were doing between
the years 1985 and 2009.
All those years you spent getting your education,
building a resume."
"Mr. Gorbachev, tear down that wall."
"Getting married.
Buying a home."
"The Hubble Space Telescope is released."
"Having children."
"Can you explain what internet is?"
"Building up retirement."
"O.J. Simpson not guilty of the crime."
"Watching your children grow up.
Funerals of your family members and your loved
ones.
"iPhone."
"I mean it's just an enormous amount of time.
You come out and how are you supposed to explain,
'Well I was convicted of murder but I didn't do it.'
That baggage stays with you, forever.”
Robert Lee Stinson was convicted of murder
on the basis of forensic bite mark evidence.
He refused to admit guilt, so he was never
granted parole.
By 2003, he’d been in prison for 18 years.
That’s when when he wrote to the Innocence
Project at the University of Wisconsin.
“It was a request for assistance saying
that he was innocent and that he was convicted
on bite mark evidence.”
They took the bite mark evidence out of storage
and sent it to four forensic odontologists
to review.
And they found that the dentists who testified
against Stinson, L.T. Johnson and Raymond Rawson,
had made a “series of errors that resulted
in an incorrect determination.”
They said Johnson’s technique of placing
a semi-opaque overlay on top of the bitemarks
obscured the fact that they didn’t match.
And they showed how misleading it could be
to hold a dental model up to a bite mark impression,
which Johnson had done in front of the jury.
It makes it look like Stinson’s teeth fit,
but it also looks like these three random
sets of teeth fit too.
Overall, they concluded that “Stinson can
be excluded from” having made the bite marks.
“We said look, it's not him.
And the prosecutors looked at it and they
said we gotta talk to Dr. Johnson and they
came back and they said, no we stand by it.
It's him.
Where? how can you see that?
But they did.”
Fortunately, the bite marks weren’t the
only physical evidence in the case anymore.
The same day Stinson was convicted, December
12th, 1985, a paper was published in the journal
Nature reporting that DNA could be used in
forensics.
“It is evidence that promises a breakthrough
future for law enforcement officials.”
“These genetic fingerprints are a powerful
tool for solving mysterious crimes.”
We know today that DNA is a powerful form
of evidence, but it’s worth digging into
why that is.
In our cells, there’s a small section where
a short DNA phrase gets repeated several times.
We all have it in the same location, but the
number of repeats varies between people.
I might have 9.
You might have 15.
We have instruments that can essentially count
the repeats by their size.
And because we can count them, we can survey
a bunch of people to see how common each number is.
So let’s say police find a DNA sample with
9 repeats.
Well if 30% of people have 9 repeats, that’s
not very strong evidence.
But scientists have identified more than 13
different locations on our DNA where we vary
in these kinds of repeats.
And we have two numbers for each location
because we inherit one from each parent.
So maybe I have 9,9 at one location; 14,16
at another; 12,10 at a third, and so on.
The more locations you add, the smaller the
number of people who could match.
That’s what makes DNA so powerful: our samples
are unique, they distinguish us from each other.
But it’s also quantifiable, so we can calculate
how much it distinguishes us.
It comes with statistics.
Compare that to fingerprints.
We suspect they’re quite unique, but we
can’t calculate how unique because fingerprints
lack the kind of universal structure that
the DNA molecule has.
Instead of looking at a predetermined location
and counting up repeats, fingerprint examiners
have to decide what’s notable about each
print.
“And there are so many different permutations
so that makes it very difficult to say well
this particular configuration is one in a
million or one in a quadrillion or whatever
the way you could do with DNA.”
Rsearchers have started figuring out what
to measure in a fingerprint to get useful
statistics.
But the other pattern-matching disciplines
are further behind.
And with bite marks, it might not even be
worth trying.
In 2010 the federal government gave L.T. Johnson
a $700,000 research grant to make bitemark
analysis more scientific, using statistics.
His team borrowed live pigs and made bite
marks in their skin with dental models.
They used software to measure the bite marks
for tooth width, angle, and spacing.
And when those measurements were used to guess
the source teeth,
they identified the correct dental model only
2% of the time.
Even in these controlled conditions, skin
did not reliably record the dimensions of teeth.
But that was already becoming painfully clear.
"Wrongly convicted."
"Wrongfully convicted."
"Wrongfully convicted
of rape.""
He spent more than 10 years in prison
before DNA evidence identified the real killer."
"The science in this case was just plain wrong."
"Bite mark analysis is now being questioned
nationwide."
As DNA testing began overturning bite mark
convictions around the country,
the Wisconsin Crime Lab was analyzing the
bra and shirt that the victim in Stinson’s
case was wearing when she was killed.
The male DNA they found on several areas on
her clothing didn’t match Stinson’s DNA.
He was excluded as the source again, and again,
and again.
By 2008, a full DNA profile was developed
from the blue v-neck pullover and entered
into a DNA databank.
Two more years would pass before it yielded
a match.
But in the meantime, the District Attorney’s
office finally agreed that Stinson’s conviction
should be vacated.
And he was released from prison on January
30, 2009.
“I remember the scene of when we walked
him out.
There was media there.”
"It was an emotional day for Robert Stinson
and his entire family.”
“Well it was very powerful when we saw Robert
Lee Stinson walk out of this prison this morning.”
“And we stood outside the prison gates and
they opened up a sliding chain link gate and
it was a it was actually a rather subdued,
almost melancholy moment where his sister
greeted him with a deep hug.”
“Finally justice is done.
But at what cost?”
"I can't explain it.
I can't explain this.
It's been a long ride for me.
And I'm finally out and I'm going to enjoy my
life now."
“I think the lesson we have and this is
I think regrettable, is that no matter how
careful you are, how cautious you are, how
objective you think you are in these cases,
you can still be wrong.”
“I felt bad.
I felt bad.
You know, all I can say is you know to this
case and I think it's the only wrongful conviction
that I know of that I presided over, I'm just
grateful we don't have a death penalty.”
The year Stinson was exonerated, the National
Academy of Sciences released a report that
rocked the field of forensic science.
“That report was big.
It had huge ripple effects throughout the
community.”
“What it did was really to explode the problem
and to say to the world we have a serious
issue here.”
It found that “no scientific studies”
supported bite mark identification.
And the problem was bigger than that: it said
“a number of forensic science disciplines”
were lacking basic research.
“It mostly said you need more science in
forensic science.
Unfortunately it was received somewhat defensively
by the forensic science community and I think
that slowed down our ability to respond to
it, to learn from it, to grow from it.”
The report recommended the creation of a new
federal agency to direct and fund forensic
science research, and serve as a scientific
authority for the criminal justice system.
“And so when you come into court there would
be a bible of this information and the prosecutors
would have to work with that, and defense
attorneys would have it available to them,
and juries would be instructed accordingly.”
But Congress never created the new agency.
And by 2016, an Obama administration report
still found few studies that were appropriately
designed to assess validity.
Only the fingerprints and firearms fields
had begun to properly measure how accurate
their examiners are.
Academic researchers haven’t really taken
an interest in running these studies.
And even if they did, they’d need access
to forensic examiners and lots of test samples.
And in the crime labs, they don’t necessarily
have the resources or incentives to participate.
“You don't have to talk to very many lab
directors to find out that they are overburdened
and they're undermanned.
You don't really have the freedom to say hey
I think I'll take a third of my people and
conduct some error rate studies.”
“Our problem now is just trying to get the
studies done.”
Without some permanent infrastructure to continually
examine the accuracy of the forensic sciences,
we can’t be sure that a case like Robert
Lee Stinson’s won’t happen again.
“The detectives that picked you up yesterday.
Did they tell you what this was about?
Why you’re here?
About a homicide.
Do you what DNA is?”
A year after Stinson’s release, the DNA
from the victim’s blue v-neck pullover finally
solved the crime.
“They got a cold hit, that is they weren't
looking for anybody in particular they just
ran the profile through the database and it
hit.”
His name was Moses Price Jr., and he wasn’t
a suspect in the original police investigation.
Around the same time that Stinson was arrested,
Price pled guilty to two armed robbery charges.
He’d also been accused of rape.
And in 1991, as Stinson sat in prison, Price
beat a man to death and set his house on fire.
“Your DNA wasn’t taken until just recently.
It matched to DNA on her body, and I’m hoping
that you’ll explain what happened here.”
When the DNA match prompted police to question
him, Price confessed.
He said he remembered following a woman one
night in November 1984.
He was drinking and said he blacked out.
“All I know is when I came to, I was on
top of her.”
Price said if he’d known Stinson had been
convicted for the murder, he would have stepped
up a long time ago.
“You never heard that anyone had been arrested
on it?
“No.”
“He spent, you know, since 1985 in prison.”
“What would you want to say to him, Moses?
“I’m sorry.”
Thank you for watching False Positive.
If you have any questions about this story
or how we made this series, I'll be doing
a live Q&A for our Video Lab members— that's
our paid membership program.
It'll be Thursday, February 7th at 5PM Eastern
and it'll be moderated by my colleague Johnny Harris,
who you may know from our Borders series.
Feel free to leave your questions in the comments
below and if you can't make it to the live
stream, don't worry, all members will still
be able to access the Q&A after the fact.
Thanks.
