The BBC's Jeremy Buxton: "More than 40 officers carried out inquires and forensic tests"

Philip Heyward, 64, a tree surgeon, is thought to have bludgeoned mother-of-three Phyllis Mary Heyward, in her 50s, and her parents Albert and Myra Spring, both in their 80s, to death.

The attack took place in a home belonging to Mrs Heyward's sister Shirley Soloman in Bethel Road, St Austell, Cornwall.

The bodies of Myra and Phyllis were discovered in the kitchen and that of Albert was found at the top of the stairs. All three had died from head injuries, probably inflicted with an axe.

Axe recovered

Police have not disclosed how Mr Heyward died, but he is believed to have returned to his own home at nearby St Blazey Gate and set fire to it.

BBC Radio 5 Live: "Between 0730 and 0800, there was a disturabance at the house"

His body was discovered on the upstairs landing of the badly burnt-out house. An axe was also recovered.

Detective Inspector Dave Rowe confirmed police are not looking for anyone else in connection with the incident.

"Police have been involved with domestic incidents concerning two of these people recently, in the last two months. I am not willing to go into the nature of those incidents at the moment," he said.

House to house enquiries

The first body - that of Mr Heyward, was found after firefighters were called to a blaze at his home at 0930 on Tuesday.

The other bodies were discovered approximately half and hour later by a nurse.

A Home Office pathologist, Dr Gyan Fernando, examined the scene at Bethel Road.