Conspiracy, Aiding and Accessory Charges in Ontario

By Robb MacDonald · Updated 6 October 2026

Conspiracy is an agreement between two or more people to commit an offence, and it is a crime even if the offence never happens. Aiding or abetting means helping or encouraging someone to commit an offence that is committed, which makes you guilty of it. An accessory after the fact helps someone escape after the offence.

What is the difference between conspiracy and aiding and abetting?

Timing and what has to happen. Conspiracy is about the agreement itself. Once two people genuinely agree to commit an offence, the conspiracy is complete, and nobody has to do anything further. Aiding and abetting is about helping with an offence that actually takes place. If the offence never happens, there is no one to aid, and the charge falls away, though attempt or counselling charges may remain.

The consequences differ too. A person who aids or abets is a party to the offence and is convicted of that offence, subject to its full penalty. A conspirator is convicted of conspiracy, which carries its own penalty under section 465.

Then there is the accessory after the fact, which most people confuse with the other two. It has nothing to do with helping commit the offence. It is about helping someone get away afterwards, and it is a separate, lesser offence.

What does the Crown have to prove for conspiracy?

Under the Supreme Court's decision in R. v. Cotroni; Papalia v. R., [1979] 2 S.C.R. 256, the Crown must prove an intention to agree, a completed agreement, and a common design to do something unlawful. Each is a real hurdle.

The agreement has to be genuine and shared. Talk is not enough, and neither is knowing that someone else is planning a crime. Two people must actually agree, each intending to carry the plan out. That is why, under R. v. O'Brien, [1954] S.C.R. 666, there is no conspiracy where the only other person never intended to go through with it. This often matters in cases built on an informant or an undercover officer.

There is also no offence of attempting to conspire. The Supreme Court held in R. v. Déry, 2006 SCC 53, that trying and failing to reach an agreement is not a crime.

The penalties in section 465 track the planned offence. Conspiracy to commit murder carries a maximum of life imprisonment. Conspiracy to commit any other indictable offence carries the same maximum as that offence. A conspiracy formed in Canada to commit an offence abroad can also be prosecuted here.

Can you be convicted of conspiracy if the crime never happened?

Yes. This is why conspiracy is so often charged in drug and fraud cases, where police may step in before the planned offence takes place. The offence is the agreement, so the Crown does not need to prove that anyone took a step towards carrying it out.

The same point means withdrawal usually does not help on liability. Once the agreement is made, the conspiracy is complete, and backing out afterwards does not undo it, although it can matter on sentence.

What makes someone a party to an offence?

Section 21 makes everyone a party who actually commits the offence, does or omits anything for the purpose of aiding someone to commit it, or abets it. Abetting means encouraging, instigating or promoting. A party is guilty of the offence itself, just as if they had committed it.

Two limits do most of the work in defending these cases. The first is that being present is not enough. A person who stands by while a crime happens is not a party unless they did something, or failed to do something they had a duty to do, for the purpose of helping. The second is knowledge. In R. v. Briscoe, 2010 SCC 13, the Supreme Court held that an aider must know, or be wilfully blind to the fact, that the other person intends to commit the crime, and must intend to help.

Robb has seen the presence point decide a case early. In a 2025 murder preliminary inquiry with three co-accused, his associate Michael Kachkar describes the Crown's main witness telling the court that their client had been nothing but an observer. The client was discharged mid-inquiry while the co-accused went on to trial. You can read more in the 2025 record.

Section 21(2) adds a second route, common intention. Where two or more people form an intention to carry out one unlawful purpose and help each other with it, each is a party to any further offence one of them commits, if they knew or ought to have known it would probably happen. For murder and attempted murder, the Supreme Court has held that the Charter requires actual foresight, so "ought to have known" is not enough.

A related liability covers someone who counsels an offence. Under section 22, a person who counsels, procures, solicits or incites an offence that is committed is a party to it. Under section 464, counselling an offence that is never committed is still a crime, punished as if it were an attempt.

What is an accessory after the fact?

Under section 23, an accessory after the fact is someone who, knowing that a person has been a party to an offence, receives, comforts or assists them so that they can escape. Typical examples are hiding someone, driving them away, or disposing of evidence to help them avoid arrest.

Knowledge is the centre of these cases. The Crown has to prove that the accused knew the other person had committed the offence, not just that something had happened. The Ontario Court of Appeal held in R. v. Duong (1998) that wilful blindness can satisfy that requirement, but suspicion alone does not.

The penalty is set by section 463. Where the main offence carries life imprisonment, the maximum is 14 years. Otherwise it is half the maximum for the main offence. Accessory after the fact to murder is the exception: section 240 sets a maximum of life.

How are these cases proved, and how are they defended?

Conspiracy and party cases are usually circumstantial. The evidence tends to be intercepted calls and messages, phone location records and surveillance, often with a co-accused or informant to tie it together. Disclosure is often enormous, and much of the defence work is reading it closely enough to separate what the client actually said and did from what others said about them.

There is a special rule of evidence here that clients need to understand. Under R. v. Carter, [1982] 1 S.C.R. 938, statements made by one conspirator in furtherance of the conspiracy can be used against the others. But only once the court is satisfied, on evidence directly admissible against the accused, that they were probably a member of it. A defence that keeps the Crown from clearing that step can keep much of the most damaging evidence out of the case.

A co-accused's decisions do not decide yours either. In R. v. Kidane, a Superior Court jury trial in June 2013, the co-accused pleaded guilty to a seven-year sentence on the first day. Robb's client went ahead. After Robb's cross-examination of the three police officers who said they had watched the robbery from a surveillance van, the client was acquitted of all charges. Read about R. v. Kidane. Past results do not guarantee future outcomes.

Get advice before you explain yourself

People charged as parties often want to tell police that they were only there, or only drove, or did not know what was planned. That explanation may be true and still be the evidence that convicts them, because it places them at the scene and supplies the knowledge the Crown is missing. Speak to a lawyer first.

Robb MacDonald has practised criminal defence for more than twenty years, including homicide, drug and fraud cases where conspiracy and party liability are often charged. He earned his J.D. at Queen's University in 2006, was called to the Ontario bar in 2007, and trained under Edward Greenspan QC. He is a two-time provincial advocacy champion (Arnup Cup, OTLA Cup) and is in court about five days a week. Every Ontario lawyer is regulated by the Law Society of Ontario.

Call (416) 315-1505 or email rm@lawintoronto.com. The office is at 130 Spadina Ave. #606, Toronto, ON M5V 2L4, and Robb answers day and night. You can also request a confidential consultation.