A mother and her 13-year-old son have died after being stabbed in their home.
The woman, her husband and the child were found with serious stab wounds by emergency crews called to Greyhound Lane, Norton, Stourbridge, just after 08:00 BST.
A Land Rover taken from outside the house was intercepted by police about 30 minutes later in Norton Road.
A man, in his 20s, has been arrested on suspicion of murder and wounding.
The husband and wife have been named locally as Peter and Tracey Wilkinson.
West Midlands Police said it understood the suspect was known to the family and may have been living at the address, although he was not a family relative.
The 13-year-old boy suffered critical stab injuries and was later pronounced dead in hospital.
The husband remains in hospital with stab wounds to his chest and back.
He is believed to be a company director. A spokesman for the firm Hill & Smith Ltd said: "We don't have any comment to make at the moment."
Police said as the Land Rover was intercepted, it was in collision with a police car.
The force said two officers were taken to Russells Hall Hospital, in Dudley, with minor injuries. They have since been released.
Supt Lee Kendrick, of Dudley Police, said: "What has unfolded here this morning is horrific and heart-breaking. Police and ambulance were confronted with an awful scene: a man, woman and boy all with very serious stab injuries.
"The woman and boy were found in the house and the man in the garden."
He added that "tragically" there was "nothing that could be done" to save the woman, understood to be in her 50s, who was pronounced dead at the scene.
Supt Kendrick said they "don't think this was a burglary or a robbery".
The man in his 20s would be questioned on suspicion of murder and wounding, the force said.
The police are not looking for anyone else in connection with the attack.