Four Australian police officers were killed Wednesday evening (Australia time) in a traffic crash in Melbourne.

The accident happened on the Eastern Freeway in Melbourne, about 5.40pm after two officers pulled over a Porsche 911 for speeding. The officers then decided to impound the Porsche, News.com.au reports.

Two more officers arrived in an unmarked car for backup. A large, refrigerated semi-trailer crashed into all four of them, leaving behind a scene of “utter carnage” and making “considerable contact” with the Porsche, witnesses said.

The fallen officers are two male constables, one female senior constable and one male senior constable. It is believed one of the officers was new to the force, while the others were more “seasoned and experienced”.

Victoria Police Chief Commissioner Graham Ashton said they did not believe the driver of the Porsche was injured and he de-cided to flee the scene on foot. He said the Porsche had been driving at excessive speed on the freeway which caused police to pull him over and it wasn’t unusual to impound a vehicle under that offense.

Reports say police are searching for the driver of the Porsche.