Evidence: An Introduction

Evidence is the usual means of proving or disproving a fact, or matter at issue.

The most common method of giving evidence in a court situation is by oral testimony under oath or affirmation. Oral testimony is often supported by 'producing exhibits ', which means depositing physical or documentary evidence with the Court. Note that 'document' in the (EA) includes any material from which symbols, images or sounds can be derived, as well as information electronically recorded and stored. Oral testimony establishes the relevance and accuracy of the exhibit.

It may be helpful to think of evidence in three categories:

  1. Evidence about the identity of the offender. If your case fails, it is likely to be on these grounds. You can see what was done, but you cannot prove who did it, or permitted it, or which person is culpable as a principal under s340 of the RMA.

  2. Evidence about the act or action itself. Occasionally this is an issue, especially on technical or subjective matters.

  3. Evidence about intent to commit the act or action (this is not required in ‘strict liability’ offences).

The fundamental principle: relevance

All relevant evidence is admissible, unless there is some policy reason to exclude it (refer s7 of the EA). The policy reasons can be summarised by reference to s6 of the EA. The admission of evidence should:

  • recognise the importance of the rights affirmed by the New Zealand Bill of Rights Act 1990

  • promote fairness to parties and witnesses

  • protect rights of confidentiality and other important public interests

  • avoid unjustifiable expense and delay.

As explained above, relevant evidence is evidence that tends to prove or disprove an element of an offence. The extent of this tendency is known as the probative value of the evidence. The probative value of evidence must outweigh any risk that it will have an unfairly prejudicial effect on the proceeding - or needlessly prolong it (refer s8(1) of the EA).

Obligation of fairness

Every act by a public authority which is carried out under a legislative power is governed by the principles of 'natural justice'. This means that the process or approach must be fair. There is no statutory formula for fairness, but relevant matters in an investigation would include:

  • keeping an open mind during inquiries

  • not targeting a particular defendant unless evidence supports that

  • being fair in dealings with a defendant.

The obligation continues past the laying of charges to disclosure of the prosecution case (which should be full and timely).

The attitude of the investigator is important. The investigator is an employee of an authority, but more importantly an officer of the public system of justice which has the interests of the community at its heart. It is not the role of an investigator to get convictions for offences, but to establish what actually happened; and if charges are laid, to assist the court in making a correct decision. Intuition may assist in developing lines of inquiry, but personal beliefs should not close off alternative lines too early.

Improperly obtained evidence

The obligation to be fair in relation to the collection of evidence, is now legislated in s30 of the EA. A judge may exclude evidence obtained improperly or unfairly (refer s30(5)of the EA).

The judge must make a decision about whether to exclude evidence if a defendant or the judge raises the issue of it being improperly obtained. The decision is made by weighing the impropriety against the "need for an effective and credible system of justice." In particular the judge may have regard to the matters set out in s30(3)(a)-(h) of the EA:

  1. the importance of any right breached by the impropriety and the seriousness of the intrusion on it

  2. the nature of the impropriety, in particular, whether it was deliberate, reckless, or done in bad faith

  3. the nature and quality of the improperly obtained evidence:

  4. the seriousness of the offence with which the defendant is charged

  5. whether there were any other investigatory techniques not involving any breach of the rights that were known to be available but were not used

  6. whether there are alternative remedies to exclusion of the evidence which can adequately provide redress to the defendant

  7. whether the impropriety was necessary to avoid apprehended physical danger to the police or others

  8. whether there was any urgency in obtaining the improperly obtained evidence

Section 30 of the EA should remind investigators that they need to consider the different lines of inquiry available, if a potential offender's rights and freedoms may be restricted by the approach taken. An example is the choice to use search warrants before attempting to interview suspects and determine their willingness to provide information, when urgent action is not critical to securing evidence which may be at the site.