The Crime Book

215

See also: John Leonard Orr 48–53 ■ The Lindbergh Baby Kidnapping 178–85 ■ Colin Pitchfork 294–97

MURDER CASES

The Henry system, used in most countries today, classifies

fingerprints by four basic patterns – the arch, the loop, the whorl,

and the composite. It is named for Sir Edward Richard Henry, who

founded the Scotland Yard Fingerprint Bureau in 1901.

COMPOSITES

are a combination

of arches, loops,

and whorls.

ARCHES

produce a wave-

like pattern.

Tented arches rise

to a sharper point.

LOOPS

curve back on

themselves to

form a loop shape.

WHORLS

form circular or

spiral patterns.

Fingerprinting

Although it has been known

since 200 bce that each person’s

fingerprints are different from

every other person’s, Sir William

James Herschel, a British

magistrate in India during the

1850s, is credited with the first

systematic use of fingerprints for

identification. In 1891, English

scientist Sir Francis Galton

developed Herschel’s findings.

Galton devised an efficient

system that allowed fingerprints

to be matched against each

other. He discovered that every

person has a different pattern of

ridges and valleys on the pads

of their fingers (and on their

toes) that do not change with

time and will even grow back

in their original form if the digit

is damaged. In his classic book

Finger Prints (1892), Galton

referred to the lines, ridges, and

shapes of fingerprints as “little

worlds in themselves.”

Three types of fingerprints can

be recovered from a crime scene.

Patent prints can be made by

blood, grease, ink, or dirt, and

are easily visible to the naked

eye. Latent fingerprints are not

visible – they are impressions

secreted on a surface or an

object by sweat and oil on the

skin surface. Plastic prints,

which are visible to the naked

eye, are 3D indentations that

occur when a finger touches a

soft, malleable surface.

Although fingerprinting has

stood the test of time, since the

1990s, several court cases have

challenged their interpretation.

Tests have found a margin of

error, and there have been “false

positives” – two prints can be

similar enough to fool experts.

In 2002, a US federal judge ruled

that fingerprint witnesses can

no longer tell juries that two

prints are a “definite match”.

Fingerprinting may soon be

replaced with DNA tests.

Stratton’s thumb print alongside

the thumb smudge on the cash box,

and pointed out 11 characteristics

that agreed in the prints.

The defence counsel, Mr Rooth,

attempted to cast doubt on

fingerprinting as a scientific

technique, and on the reliability of

the work carried out by Collins’s

department. Rooth argued that the

print taken at the crime scene did

not match the one taken while

Alfred Stratton was in custody.

In a stroke of genius, Collins

offered to take the prints of a jury

member to show the court that

differing amounts of downward

pressure could account for the

deviation. The jury was convinced

by his scientific demonstration and

took less than two hours to deliver

a guilty verdict. The brothers were

later sentenced to death. It was the

first murder conviction in the UK

based on fingerprint evidence.

The high-profile media coverage

caused one drawback: criminals

became aware of the precautions

they had to take to avoid detection

by this new forensic tool. ■

The up-to-date professional

criminal now seeks to prevent

the leaving of telltale prints by

covering the fingertips with

thin india-rubber, gold-beater’s

skin, or silk finger-stalls.

The Mirror

212-215_Alfred_and_Albert_Stratton.indd 215 02/12/2016 15:03