INVESTIGATORS believe a blaze which caused tens of thousands of pounds damage to a house may have been started deliberately by burglars to cover their tracks.

At about 1.30pm yesterday, a passing police officer noticed smoke coming from The Mount, a large detached house near Blackhall Rocks, County Durham.

Firefighters managed to save the building but the interior was badly damaged.

A large amount of property is believed to have been taken before the fire broke out.

A police spokesman said those responsible may have been in the house for some time.

Det Con Phil Keightley said there was evidence to suggest the fire had been started deliberately.

"The property involved sits in an elevated position and the house and drive can be seen from the A1086.

"It is a busy road and we would like to hear from any motorist who noticed vehicles coming in or out.''

Anyone with information should call police on 0191- 586 2621.