In a drug case, what evidence can the defence call to show I did not know about the drugs?

Many drug cases turn on one question: did the accused know about the drugs? A person may say the bag belonged to someone else, the car was borrowed, or a parcel arrived unexpectedly. This article explains, from the witness-box angle, how that defence is presented. For the law on drug charges generally, see our guide on drug charges in Malaysia. The defence must always be built on the truth; this is not a guide to inventing a story.

Why does knowledge matter, and what are the presumptions?

To prove possession, the prosecution generally has to show custody or control and knowledge of the drug. The Dangerous Drugs Act 1952 makes this easier for the prosecution through presumptions in section 37. For example, a person found with a drug in their custody or control may be presumed to have known its nature, and possession of more than a certain quantity can raise a presumption of trafficking.

In Alma Nudo Atenza v Public Prosecutor (2019), the Federal Court held that the prosecution cannot rely on one presumption to trigger another (the so-called "double presumption" in section 37A was struck down), and confirmed that a presumption is rebutted on the balance of probabilities. That standard is lower than proof beyond reasonable doubt, but the defence still needs credible evidence.

When does the defence give evidence?

At the end of the prosecution case, the court decides whether a prima facie case has been made out. If not, the accused is acquitted. If so, the defence is called, and the court explains the accused's options. This is when defence evidence is presented.

What evidence can show lack of knowledge?

Depending on the facts, defence evidence may include:

1. The accused's own evidence. A clear, truthful account of how they came to be where they were, whose property it was, and what they knew. The accused is cross-examined by the prosecution.
2. Defence witnesses. For example, the owner of a borrowed car, a person who asked the accused to deliver a parcel, or someone who can explain who else used a room.
3. Phone records and messages. Messages showing the accused was asked to collect a "parcel" without being told its contents, or call logs showing contact with another person. These are usually proved under the Evidence Act's provisions for computer-produced documents.
4. Travel and location records. Flight records, toll and parking data, or work schedules showing where the accused was.
5. Financial records. Absence of unexplained payments can support a claim of innocent involvement.
6. Access evidence. Who had keys, who rented the house, who else used the vehicle.

The weight of each piece depends on how it fits the whole picture. Courts look carefully at whether a defence was raised early, for example in the accused's statement to the police, or only at trial.

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Can the defence challenge the prosecution's scientific evidence?

Yes. Cross-examination of prosecution witnesses, and sometimes defence evidence, may address:

• the chain of custody: whether the exhibits seized are the same ones analysed by the chemist;
• the chemist's analysis: methods, weights and whether the substance is a listed drug;
• police handling: how the search was done, who was present, and whether marking and sealing were properly recorded;
• fingerprint or DNA evidence, or the absence of it.

These are technical issues for your lawyer, who may consider whether independent expert evidence is needed.

What is an alibi notice?

If the defence is that the accused was somewhere else at the relevant time, section 402A of the Criminal Procedure Code requires written notice of the alibi to be given to the prosecution in advance, with particulars, as the section sets out. Without proper notice, the court may refuse to allow the alibi evidence. Tell your lawyer about any alibi early.

What should I prepare with my lawyer?

• A truthful, detailed timeline of the events, from your own memory.
• Names and contact details of people who can confirm facts.
• Phones, accounts and records that may support your account, preserved without deleting anything.
• Your police statement, if available, to understand what you said earlier.

Never ask a witness to say something untrue, and never alter or delete messages. Fabricating evidence is a serious offence under the Penal Code and would destroy a genuine defence.

Common mistakes

• Changing the story at trial from what was said to the police, without a truthful explanation.
• Calling witnesses who have not been interviewed carefully, and whose evidence contradicts the accused.
• Deleting messages that could have helped, or hurt, the defence.
• Missing the alibi notice requirement.
• Overstating ignorance, for example denying any connection to a room the accused plainly used.

When to speak to a lawyer

Immediately. Drug charges carry very serious consequences, and early steps, such as preserving records and identifying witnesses, can matter greatly. Legal aid may be available through the Legal Aid Department or the National Legal Aid Foundation. Chris & Partners, led by Dr Chee Hui Bing, handles criminal defence work. Contact us; every case depends on its facts.

Frequently asked questions

Do I have to give evidence?

When the defence is called, the court explains your options. Your lawyer will advise you on the choice in your case.

Can my family members be defence witnesses?

Yes, if they have relevant, truthful evidence. Their evidence will be tested in cross-examination like any other witness.

What if my phone was seized by the police?

Tell your lawyer. There are procedures to request access to, or copies of, relevant material.

Does "I didn't know" alone rebut the presumption?

It depends on the whole evidence. A bare denial without supporting facts may carry little weight.

Is the standard the same for the prosecution and the defence?

No. The prosecution must prove its case beyond reasonable doubt; a presumption is rebutted on the balance of probabilities.

Sources & fact check

Legal points in this article were checked against the primary sources below. The law can change; this is general information, not legal advice.

1. Dangerous Drugs Act 1952 (Act 234), AGC Laws of Malaysia
2. Alma Nudo Atenza v Public Prosecutor [2019] 4 MLJ 1 (Federal Court) (reported judgment)
3. Criminal Procedure Code (Act 593), Attorney General's Chambers Laws of Malaysia
4. Evidence Act 1950 (Act 56), including section 114A, AGC Laws of Malaysia
5. Penal Code (Act 574), Attorney General's Chambers Laws of Malaysia
6. Legal Aid Department (Jabatan Bantuan Guaman), Prime Minister's Department

Fact-checked on 17 Oct 2026