Two men and a 16-year-old boy were killed when a car caught fire following a crash in Cornwall on Tuesday.
Police rushed to the A390 near Saint Ive, Liskeard, shortly before midnight on 18 April after a car was reported to have left the road and caught fire.
The youth and two men, aged 18 and 30, were found inside and declared dead at the scene.
Four teenagers, two boys and two girls from Liskeard were later arrested on suspicion of causing death by dangerous driving and remain in custody, Devon and Cornwall Police confirmed on Wednesday.
Officers have also seized a vehicle believed to have been involved in the “tragic incident”.
Sergeant Tina Green, of Devon and Cornwall Police, said: “Our thoughts are with the families and friends of those who lost their lives and our investigation remains ongoing to understand the full circumstances of how this tragic incident occurred.
“Whilst our inquiries are ongoing there will be an increased police presence in the area of the collision and in the wider Liskeard area.
“I would encourage anyone with information which might assist police and anyone who was travelling in the area and may have relevant dashcam footage to report it to us.
She added: “We are aware of some comments and speculation on social media and I would remind the public that there is a live and active police investigation in relation to this incident and therefore please refrain from speculating about the nature of the incident and those involved.
“If you see any social media commentary that you feel may assist our investigation, please report that to us also.”
