Westerhausen, Germany - Police who thought that a married couple in Germany had committed suicide after poisoning their four children admitted Friday the theory had been wrong: The whole family was struck down by carbon-monoxide poisoning.

The father, 33, and mother, 32, were found dead Tuesday in their house in the small town of Westerhausen and the four children were alive but in an "apathetic" state. The media speculated that the parents were disturbed.

On Friday, police said the deaths appeared to have been accidental. The carbon monoxide had probably escaped from a homemade heating furnace, officials said in the town near Germany's Harz mountain range. The children are recovering.