Interrogations-and-Confessions-Handbook

624 A Psychology of Interrogations and Confessions
prove his innocence. This is particularly the case if the confession contains a
detailed post-admission narrative account with apparent special knowledge of
the crime scene. Such special knowledge in the case of innocent persons arises
through contamination (e.g. the case details were communicated by the police
or obtained through some other sources, such as from the media or the real
culprit). Recent improvements in forensic science, particularly DNA technology,
have greatly assisted in proving actual innocence. This situation has improved
considerably in England with the independence of the Forensic Science
Service from the police. However, there are still worrying tendencies for some
police forces to resist investigating available evidence that might exonerate an
accused or convicted person, or for crucial forensic evidence to become lost while
in the possession of and under the control of the police.
It is not known how frequently false confessions to the police happen and
there is likely to be considerable variability across countries due to cultural factors
and differences in police practice. There are methodological difficulties in
establishing reliable data due to inherent problems in establishing the ‘ground
truth’ (i.e. the factual basis of the confession). In cases where the confession is
the main evidence against defendants, a retraction prior to trial is essentially
self-serving and must accordingly be treated with caution. Nevertheless, there
are many documented cases where defendants have made false confessions, and
a retraction of a confession where there is no solid independent corroborative
evidence should always be investigated with an open mind. In addition, not all
false confessions are retracted and two recent studies conducted among Icelandic
prison inmates have highlighted the frequency with which people make
false confessions to the police as a way of protecting a significant other (i.e. a
peer, friend or relative). This group of false confessors has been neglected in
research, because they do not readily come to the attention of researchers and
other professionals.
False confession is undoubtedly a universal phenomenon, but considerable
cross-cultural variability is likely to exist. The higher the base rate of innocent
suspects interrogated, which is not uncommonly seen in terrorist cases and
some notorious murder cases where the police trawl in a large number of people
for interrogation, the greater the proportion of false confessions that are likely
to occur. In such cases there is often a great deal of pressure on the police to
solve the case and this often influences their methods of extracting confessions
from suspects.
Innocent suspects do sometimes give incriminating information to the police
that, on the face of it, seems to have originated from the perpetrator. Such
apparently ‘guilty knowledge’, which often makes the confession look credible,
is then used to substantiate the validity of the confession given. The lesson
to be learned from cases presented in this book is that unless the information
obtained was unknown to the police, or actually produces further evidence to
corroborate it (e.g. the discovery of a body or murder weapon), then great caution
should be exercised in the inferences that should be drawn from it about the
suspect’s guilt. Police officers will undoubtedly find it difficult to believe that
they could inadvertently communicate salient information to suspects in this
way, but it happens.