A man who was found dead in a car that collided with a tree had been stabbed.
The victim had been driving a black Toyota MR2
A post-mortem examination has revealed the man, who was found in Kendrick Road, Reading, on Wednesday evening, died from a stab wound to the heart.
Police launched an investigation following the car crash and said the man, aged in his 30s, had died before the black Toyota car crashed.
Four people are being held at Reading police station in connection with the man's death.
Police are questioning three men, aged 23, 27 and 42, and a 44-year-old woman.
Det Insp Rebecca Mears, of Reading CID, said: "The victim was driving a black Toyota MR2 in Reading last night and we are keen to speak to anyone who saw the car driving around the London Road area in a specific period between 7.45pm and 8pm."