SIXTEEN masked bandits carried out a terrifying daylight robbery on the luxury car dealership of Terry Mullens, menacing staff with guns and knives, before fleeing in four high-performance cars.

But a defiant Mullens, a well-known racehorse owner, put his life on the line and refused to let them take his prized $400,000 orange Lamborghini Murcielago, proudly parked in the middle of his showroom. "No way," he shouted at the shocked gunmen. "You're not getting the Lamborghini . . . these cars are my life."

The gang - suspected to be responsible for a string of daring raids - then made off with a Porsche Cayenne 2, a BMW M3 coupe, a black BMW 335i coupe, and a black Range Rover Sport in the raid on Thursday afternoon.

But in a bizarre twist that has totally baffled police, the cars were returned 26 hours later left parked outside the showroom seemingly in the same pristine condition as when they were stolen.

Police were only informed of the development after being contacted by The Sunday Telegraph on Saturday morning.

Investigators said the circumstances surrounding the return of the vehicles would now be probed further, as well as whether any of the cars were used to commit a crime.

Burwood police and Gangs Squad detectives returned to the car yard yesterday to take statements and tow away the stolen cars for examination.

"The cars are back, but as far as I'm concerned a crime's been committed - it's far from over," a relieved Mr Mullens told The Sunday Telegraph yesterday. "They look like they're untouched."

Reliving his robbery ordeal, Mr Mullens said: "They cornered our staff and put sets of people with each of the staff. "I'm very impressed with the way police are handling it."

Mr Mullens said the robbery occurred about 3:50pm when eight gunmen stormed into his showroom while a further eight men waited outside.

He said the gunmen watched the staff to ensure they could not call police.