Hi Eliza,
In Victoria, theft is considered intentionally taking something in someone else’s possession that does not belong to you, and that you do not intend to give back. If you want to establish theft you need to prove that the person:
- acted dishonestly when taking the property
- did not own the property
- were not planning to return it to the owner.
This is criminal theft which would be actionable by the police. There are also civil remedies available to you which will require you to institute court proceedings for a court order requiring the return of the vehicle to you. These include trespass to property and conversion. The elements you need to prove to establish conversion are:
- the person's conduct was inconsistent with the rights of the owner
- the conduct was deliberate
- the conduct excludes the owner from possession of the goods.
Depending on the circumstances of the case I would talk to the police about what they can do to assist you and if it is not something they can help you with - write a letter of demand for the return of the vehicle threatening legal proceedings and if he refuses - institute proceedings.