They set up a special incident room in Swindon after a man was killed by a local passenger train on the Gloucester-Swindon line on Saturday.

More than five hours later police went to the man's home address in the Pinehurst area of Swindon and found the body of his 18-year-old partner in her bed.

Police have named the train victim as 28-year-old Mark Hinton, and confirmed that he died from multiple injuries.

'Suspicious death'

But they declined to say how the woman he lived with, Sarah Louise Winrow, had died.

Acting Superintendent Bob Philpott said: "We are treating her death as suspicious."

It is understood that she had no apparent injuries and no weapon was found in the house.

A post mortem examination has been carried out and forensic samples have been sent for analysis.

'Terrible domestic tragedy'

Mr Philpott said inquiries were continuing and the incident room was investigating the circumstances surrounding the deaths.

"At the moment we are concentrating our inquiries on these two people only. This appears to have been a terrible domestic tragedy and it is a very distressing time for the two families concerned just before Christmas."

The policeman said the train driver reported the rail death and alerted the police.

Officers had to force their way into the victim's home, where they found the body of the young woman. She was alone in the house.

The couple had a two-year-old girl, whom Mr Philpott declined to name. He said: "She is safe and well and being cared for by relatives."

It was understood, he said, that the toddler had been staying with relatives for some time.

Wiltshire coroner David Masters has been informed and an inquest is expected to be formally opened and adjourned.