Because investigators have had only limited access to the building, the cause of the fire remained unknown today.

The police said the cause of the shooting remained under investigation.

The cause of the accident remained under investigation yesterday, the police said.

Fire officials said last night that the cause remained under investigation.

The cause of the blaze remained under investigation last night, the officials said.

The cause of the fire remained under investigation last night.

But with cyclophosphamide-8, the cause of death remains in doubt.

In each case, the cause of the blaze remains under investigation.

The cause of the fire has not been determined and remains under investigation.

The cause of the blast, he said, remains under investigation.