Home

Insights

How Are Text Messages and Phone Data Used as Evidence of Drug Trafficking in Victoria?

How Are Text Messages and Phone Data Used as Evidence of Drug Trafficking in Victoria?

Direct answer

In Victoria, police use text messages, call records, and other phone data as circumstantial evidence of drug trafficking, arguing that they show dealing. This evidence can be powerful, but it can also be challenged on how the phone was obtained, what the messages actually prove, and whether it is admissible.

This guide explains how text messages and phone data are used as evidence of drug trafficking in Victoria, what police rely on, how the evidence can be challenged, and what to do if your phone has been seized.

Written by

Lauren Tye

Principal Lawyer · Criminal Defence Lawyer

Legally reviewed by

Counsel

Independent legal review · September 2026

Read

Published

Updated
Reviewed

On this page

Key takeaways

  • Police use messages, call records, and phone data as circumstantial evidence of trafficking.
  • This evidence is used to argue that communications show dealing, not personal use.
  • How the phone was seized and searched can affect whether the evidence stands.
  • What a message actually proves is often open to interpretation.
  • The admissibility of the evidence can be challenged in the right case.
  • What you say about a phone or passcode can affect the case, so advice matters early.

Who this is for

Written for

  • People whose phone has been seized in a drug investigation
  • Anyone charged with trafficking based partly on phone data
  • People unsure what their messages can be used to prove
  • Anyone wanting to understand how phone evidence is challenged
  • People facing a drug charge built on communications

Not a substitute for

  • Legal advice about a specific trafficking charge
  • Representation at a committal, plea, or trial
  • Advice on whether phone evidence can be excluded in your case
  • Advice about the trafficking charge itself
  • Advice about Commonwealth drug offences

Plain-English definitions

Circumstantial evidence

Evidence that points to a conclusion by inference, rather than proving it directly.

Phone data

Messages, call records, contacts, photos, and app data stored on or from a phone.

Tick sheet

A record of amounts, names, or debts that police may say shows dealing.

Indicia of trafficking

Signs, such as messages or records, that police argue point to dealing.

Admissibility

Whether evidence is allowed to be used in court.

Warrant

A legal authority that can allow police to search a device or premises.

Extraction

The process of downloading data from a seized phone.

Trafficking

Selling, offering, preparing, or possessing a drug of dependence for sale.

Legal process timeline

  1. 1

    The phone is seized

    Police take a phone during a search, arrest, or investigation.

  2. 2

    Extraction

    The phone data is downloaded and examined for evidence.

  3. 3

    Building the case

    Police identify messages, records, and data said to show trafficking.

  4. 4

    The charge

    You are charged, with the phone evidence forming part of the brief.

  5. 5

    Analysing the evidence

    Your lawyer examines the extraction, the warrant, and what the data proves.

  6. 6

    Challenges

    The lawfulness and admissibility of the evidence may be challenged.

  7. 7

    A plea or a contest

    With advice, you decide how to respond to the case.

About this guide

Legal basis

This guide is based on the trafficking offence in the Drugs, Poisons and Controlled Substances Act 1981 (Vic), the police powers used to seize and search phones, and the rules that govern whether evidence is admissible.

How this guide was prepared

Drafted for people facing a trafficking charge built partly on phone data, based on the questions asked when messages and records are used as evidence.

Important limits

This article does not cover every situation. It does not specifically deal with:

  • Whether evidence can be excluded on your particular facts
  • The trafficking charge itself, which is dealt with separately
  • The technical detail of phone extraction
  • Commonwealth offences and interception laws
  • The precise strength of the case against you

Whether phone evidence stands depends closely on how it was obtained and what it proves.

In-depth analysis

How Police Use Phone Data in a Trafficking Case

How do police use phone data as evidence?

As circumstantial evidence that the communications show dealing rather than personal use. Police examine messages, call records, contacts, and app data, and argue that references to amounts, prices, meeting points, or repeat contacts point to trafficking. Understanding what happens after a charge helps you see where this evidence fits.

The prosecution rarely relies on the phone alone. Phone data is usually presented alongside the drugs, cash, or other items, so that the communications support an overall picture of trafficking. The way police rely on phone data is best understood as one strand of a circumstantial case.

What kinds of messages do police rely on?

Messages that appear to discuss amounts, prices, or supply. Police point to texts that seem to arrange sales, records that look like a tally of amounts or debts, and patterns of short contacts that they say are consistent with dealing. These are treated as indicia of trafficking rather than proof on their own.

The interpretation is where these cases are often fought. A message can be ambiguous, taken out of context, or explained innocently, so what the words actually prove, and whether they point to trafficking or personal use, is frequently in issue.

Challenging Phone Evidence

Can phone evidence be challenged?

Yes, on how it was obtained and what it proves. The lawfulness of the seizure and search, whether a warrant was required and properly obtained, and the reliability of the extraction can all be challenged, and where evidence was obtained unlawfully, its admissibility can be in issue. Thinking carefully about answering police questions matters, because your account can affect these challenges.

The meaning of the data is equally open to challenge. Whether a message truly shows trafficking, rather than personal use or something innocent, is often arguable, and a case that looks strong on the surface can weaken once the communications are examined in context.

What if the phone evidence is weak?

Then the case against you may be weaker than it appears. Where the phone evidence is ambiguous, unlawfully obtained, or does not clearly show trafficking, the strength of the whole case can fall away, which can support a charge being withdrawn or reduced.

This is why the evidence is examined so closely. Analysing the extraction, the warrant, and the meaning of each message can reveal weaknesses that shape whether the matter is contested, negotiated, or resolved.

What Happens If Your Phone Is Seized?

What should you do if your phone is taken?

Get legal advice before giving any account. What you say about a phone, a passcode, or the messages on it can affect the case, so it is important to get advice early, and our work on drug offence defence starts by examining how the phone was obtained and what the data really shows.

From there, the approach is to test every part of the phone evidence. How the phone was seized, whether the search was lawful, how the data was extracted, and what the messages actually prove are all examined, because each can affect the strength of the case.

Do you have to give police your passcode?

This depends on the circumstances, and it is a question for legal advice. Police may seek access to a phone, and there can be orders or powers relevant to passcodes, so what you are required to do is not always straightforward. Because the answer turns on the situation, you should get advice rather than assume.

Whatever the position on access, what you say about the phone matters. Volunteering explanations about messages or ownership without advice can concede more than you realise, so it is safer to seek legal advice first.

Scenario-based guidance

If your phone has been seized

How it was taken and searched can be challenged, so note the circumstances and get advice.

If the messages are ambiguous

What they prove is open to interpretation, so their meaning should be examined closely.

If a warrant may have been required

Whether one was obtained can affect admissibility, so raise it with your lawyer.

If police ask about your passcode

What you are required to do is not always clear, so get legal advice before responding.

If the phone is the main evidence

A weak phone case can undermine the whole matter, so it should be tested in detail.

If you are asked to explain messages

Volunteering an account can concede more than you realise, so seek advice first.

Practical checklist

If your phone has been seized in a drug investigation:
  • Get legal advice before giving any account.
  • Do not volunteer explanations about messages or ownership.
  • Note how and when the phone was taken.
  • Consider whether a warrant was involved.
  • Think about what your messages could be said to show.
  • Preserve anything relevant to the context of the communications.
  • Ask your lawyer about access and passcode questions.
  • Have the extraction and warrant examined.
  • Do not discuss the matter with others involved.
  • Attend every court date.

Common mistakes

  • Assuming phone messages automatically prove trafficking.
  • Explaining messages to police before getting advice.
  • Overlooking whether the search or warrant was lawful.
  • Ignoring the context that can explain a message.
  • Treating the extraction as beyond challenge.
  • Volunteering a passcode or account without advice.
  • Not testing what the data actually proves.
  • Discussing the messages with others involved.
  • Assuming a strong-looking case cannot weaken.
  • Leaving legal advice until the day of court.

Questions to ask your lawyer

  • What phone evidence is the prosecution relying on?
  • Was the phone seized and searched lawfully?
  • Was a warrant required and properly obtained?
  • What do the messages actually prove?
  • Can the phone evidence be challenged or excluded?
  • How central is the phone data to the case?
  • Do I have to provide my passcode?
  • Could the charge be reduced or withdrawn?
  • Should I contest the charge or negotiate?
  • What should I avoid saying to police?

Sources

Frequently asked questions

Police use them as circumstantial evidence, arguing that texts about amounts, prices, or supply, along with call records and contacts, point to dealing rather than personal use. They are treated as indicia of trafficking rather than proof on their own, and are usually presented alongside drugs, cash, or other items to build an overall picture.

Yes. The lawfulness of the seizure and search, whether a warrant was required and properly obtained, and the reliability of the extraction can all be challenged. The meaning of the messages is also open to challenge, because a text can be ambiguous or explained innocently, so what the data actually proves is often in issue.

This depends on the circumstances and is a question for legal advice. Police may seek access to a phone, and there can be orders or powers relevant to passcodes, so what you are required to do is not always straightforward. Because the answer turns on the situation, you should get advice before responding.

It is a record of amounts, names, prices, or debts that police may say shows dealing. A tick sheet, whether on paper or on a phone, is treated as an indicium of trafficking. What it actually proves can be argued, because such records can be ambiguous or explained in other ways, so they are examined closely in context.

Yes. Where the phone evidence is ambiguous, unlawfully obtained, or does not clearly show trafficking, the strength of the whole case can fall away. Analysing the extraction, the warrant, and the meaning of each message can reveal weaknesses that support contesting the charge, or having it reduced or withdrawn.

Authorship

Written by

Lauren Tye

Principal Lawyer, Lauren Tye Legal
Criminal defence lawyer practising in Victorian criminal matters. Lauren advises and appears in matters across Victorian courts, including bail, pleas, contested hearings, diversion, and sentencing.

Legally reviewed by

Senior Counsel

Independent legal review · September 2026
Criminal defence lawyer practising in Victorian criminal matters. Lauren advises and appears in matters across Victorian courts, including bail, pleas, contested hearings, diversion, and sentencing.

What Happens at Your First Court Date?

Can You Avoid a Criminal Conviction in Victoria?

Share this article

Keep reading

A driving while disqualified charge in Victoria can be defended. Real defences include an honest and reasonable mistake that you were entitled to drive, that you were not the driver, or that you were not actually disqualified. Each turns on the facts and the evidence.
Yes, you can go to prison for repeat driving while disqualified in Victoria. The offence carries up to 2 years imprisonment under section 30 of the Road Safety Act 1986, and repeat offending moves imprisonment from unlikely to a real prospect, though it is not automatic.
Driving while disqualified in Victoria is a criminal offence under section 30 of the Road Safety Act 1986, carrying up to 240 penalty units or 2 years imprisonment. It is heard in the Magistrates’ Court, and the court usually extends your disqualification on top of any other penalty.

Need Advice on Your Specific Situation?

The information on this page is general and is not legal advice. Speak with a criminal defence lawyer about your matter before making decisions about police, court, bail, plea, or prosecution.