The cause of death was not known, his family said.

He said a cause of death would not be known until early next week.

The cause of death was not known at press time.

Officials said the cause of the fire was not yet known.

He said the cause of the fire is not known.

The cause of the fire was not known last night.

The cause of the fire is not known, and may never be, he said.

However, she does not know the cause of his death.

Also no one knows the cause of the death which was most likely old age.

He knew its cause, but found no help in the knowledge.