A boat carrying sonar equipment heads out to look for the missing car. (Wendy Martin/CBC)

Police have temporarily suspended the search for a car that drove off the Englishtown ferry into St. Anns Bay in Cape Breton, because thick ice has moved into the bay.

Sgt. Al LeBlanc says divers decided not to resume the search on Thursday because of safety concerns related to ice that is blocking St. Anns Bay. Divers had hoped to deploy side-scan sonar again to probe the fast-flowing tidal waters.

LeBlanc says fishermen in the Englishtown area indicate the ice might not clear out for a few days after it moved in overnight.

The vehicle drove onto the ferry Monday evening and off an upright ramp, plunging into the water.

More than two days later, police are still no closer to discovering who was in the car.

Police said the small car was carried along by the strong current for about 200 metres, and then disappeared under the water.

It happened so fast that witnesses have given police little to go on.

On Wednesday, police divers used sonar to try to locate the submerged car.

While divers search, an RCMP investigator has been poring through missing persons files in Atlantic Canada and contacting other police agencies in the region.

So far that's turned up no leads.

In an effort to expand the search, police said they're preparing a bulletin that will go out to police agencies across the country.

But Staff Sgt. Craig Yorke said he isn't sure that will work either.

"With all the media around this incident, and I believe it has gone national, so with other provinces such as New Brunswick, Quebec and Ontario, you would think if somebody is missing, they would call," he said.

Another possibility is the driver could be from outside the country so if nothing turns up soon the Mounties said they will send a bulletin to police around the world through Interpol.

Police say this is still very much a mystery, and they are surprised that so far no one has come forward to say it could be a friend or a relative.

They also said they are not certain if the driver was alone in the vehicle.

The province's Department of Transportation has started an internal investigation into the incident.

Englishtown is located 61 kilometres northwest of Sydney.

The ferry runs across St. Anns Harbour connected to an underwater cable. It provides a shortcut to the Cabot Trail in northern Cape Breton.