Mystery surrounds the discovery of explosives, firearms, drugs and more than $1 million in cash at a rental property, as police appeal for information about a man caught on CCTV.

The items were found by a cleaner at a short-term rental in Keilor East, in Melbourne’s north-west, on the morning of January 24.

Police were called to the Belle Vista property about 11.30am, where they confirmed the presence of several incendiary devices.

“This was not a run of the mill seizure of drugs and cash – there were incendiary devices and a large quantity of firearms,” Detective Inspector Jamie Walker, from the Victoria Police’s major drug squad, said.

“This is organised crime.”

Members of the bomb response unit and the Australian Defence Force were also called to the property before there were several controlled detonations to render the devices safe.

The rental had been booked for several weeks in January.

Investigators interviewed a man in relation to the booking. He was released pending further inquiries.

Police have released CCTV footage of a man they believe can help them in their investigation. Photos: AAP/Victoria Police

Another line of investigation surrounds a white Toyota Camry, which visited the home several times during the booking period.

On Tuesday, police released CCTV vision of a man filling up the rental car at a service station on the Western Ring Road in Ardeer South on Christmas Day.

The man captured in the footage did not hire the car but police believe he may be able to assist them with their investigations.

Police said they had spoken to the man who hired the car, who had not been co-operative.

The vehicle was seized on January 24 and it has since been returned to the hire company.

Anyone who recognises the man from the CCTV or has relevant information is urged to contact police.

“We will track down those responsible and hold them to account,” Walker said.

“It would be in your best interests to tell us what you know now.”

-AAP