Four men wearing balaclavas burst into a house in North Yorkshire and stole shotguns and jewellery after threatening a family, police said.
Officers said the white Porsche 911 car was abandoned nearby but the family was “traumatised” by the event.
Police want anyone who saw the car or suspicious activity to come forward.
Det Insp Andrea Kell, of North Yorkshire Police, said: “A young family were left traumatised after these offenders burst into their home wearing balaclavas and threatening them with a crowbar at around teatime on Friday evening.
“The stolen firearms could be dangerous should they fall into the wrong hands, so it is important that anyone who knows where they are or who has got them comes forward as soon as possible.
“Such crimes are fortunately rare in North Yorkshire so I would appeal to anyone with any information to come forward.”
Anyone who is offered any jewellery items or shotguns for sale in suspicious circumstances is also urged to contact the police.