Forensics descended on a house in Broxburn after an armed gang dragged a man from his home and stabbed him in front of his terrified partner and child.
It is understood four men stormed the property in Cardross Avenue at 7.30pm on Monday night.
A 37-year-old man was stabbed during an attack which saw the brutes haul the victim from the house to the driveway.
The victim was found with serious injuries and taken to the Royal Infirmary of Edinburgh.
Bloodstains were seen on the doorstep of the property.

A neighbour, who wished to remain anonymous, told the Record the street was cordoned off with police and forensics.
They said: “A group of guys jumped out of a van and broke into the house.
“The attack happened in the house and he was dragged outside.
“I saw him being stretchered into an ambulance with five paramedics around him.
“There were six paramedics and two ambulances and lots of police cars in the street.
“I knew it was serious when the police cordoned off both ends of the road and started going door to door. A white van with forensic officers turned up and started going into the house.
“I’ve seen the man who was attacked out walking three or four large bulldog type dogs recently.
“He lives in the house with his partner and child.
“It has been pretty scary.”
Officers from Police Scotland say his partner and child were not injured in the incident, but were left traumatised by the vicious attack.
The suspects fled the scene in a white or silver van and drove off in the direction of Cardross Road.
Police are appealing for anyone with CCTV footage to come forward, while officers are also carrying out door-to-door enquiries surrounding the incident.
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