Family's bodies found at house in Pudsey area of Leeds
Police investigating the deaths of two adults and two children found at a house in Leeds say their inquiries will take "a considerable length of time".
The four bodies were found at the property on Sheridan Way, Pudsey, on Sunday evening.
Officers said it was possible hazardous chemicals or substances were present at the house, though they were not thought to be a risk to others.
Neighbours said the family moved into the house a few months ago.
A West Yorkshire Police spokeswoman said: "At around 1730 GMT, police were called to a property in the Pudsey area of Leeds following the discovery of four bodies.
"Inquiries are at an early stage and police have sealed off the area while the property is checked for any harmful chemicals or gases."
A Yorkshire Ambulance Service spokeswoman confirmed crews had been called to an address in Pudsey.
It said a hazardous response team had been dispatched.
Fire crews also attended the incident, a spokeswoman for the West Yorkshire Fire and Rescue Service said.