The United Nations undertook an effort to develop a set of “Principles on Effective Interviewing” to do away with torture, abuse, etc. Juan M. Mendez was the lead author of their work product….so it is oftentimes referred to as the Mendez Principles. You can review their published document below (PDF).

Here are the primary summary points:

The authorities must ensure the effective implementation of the following safeguards throughout the interview process:

a. Right to information about rights
b. Right to remain silent
c. Right to information about the reasons for arrest and any charges at the time of the arrest
d. Access to interpretation
e. Right to notify a relative or third party of one’s detention
f. Right of access to a lawyer, including through legal aid
g. Right of access to a doctor and an independent medical examination
h. Right to contact with the outside world
i. Registration of persons held in detention
j. Full recording of the interview
k. Right to review and sign the interview record
l. Right to be brought promptly before a judge or other judicial authority
m. Access to effective and independent complaints mechanisms and oversight

Some interviewees will experience a situation of heightened vulnerability when the interview intersects with certain other specific risk factors.

Such risk factors can include, for instance:
a. Age, sex, gender, gender identity or expression, or sexual orientation
b. Nationality or ethnicity
c. Cultural or religious background
d. Physical, intellectual, or psychological disability
e. Difficulties with communication
f. Difficulties in understanding (including language barriers)
g. Inability to read and/or write
h. Age-related conditions such as dementia
i. Belonging to a minority group or a marginalized socio-economic group

Accepting that “vulnerability” is a dynamic and evolving concept, other situational features that may heighten vulnerability include:

a. Health status such as injury, illness, depression, anxiety, intoxication, post-
traumatic stress disorder, or other weakened or altered state.
b. Prior traumatic experiences, including having been the subject of or witnessing abuses or human rights violations.
c. Immigration status such as asylum-seeker or refugee, unrecognized migrant
worker, irregular migrant or victim of human trafficking.
d. Being pregnant or breastfeeding, or being a primary caretaker and not having been given the opportunity to make alternative caretaking arrangements.
e. The nature of the offence under investigation such as pedophilia, political
offences, or terrorist acts.

Investigator Training:

Key elements of effective interview training include how to:
a. Keep an open mind and avoid prejudice
b. Strategically plan and prepare
c. Build and maintain rapport
d. Identify and respond to the specific needs of interviewees
e. Comply with international human rights law
f. Ensure safeguards are applied throughout the interview process
g. Employ scientifically supported questioning techniques
h. Use active listening skills and allow interviewees to respond fully to questions
i. Interact with a reluctant interviewee
j. Interact with an interviewee’s lawyer
k. Initiate and end the interview professionally
l. Conduct an analysis of the information gathered
m. Assess the interview process with a view to improving skills.