A man has been found guilty of murdering a teenager who was found stabbed to death in an upturned car.
Joshua Harling, 19, from Oxford, died from a chest wound in Chinnor Road, Thame, on 22 July.
Nathan Braim, 20, from Thame, was convicted of murder following a seven-week trial at Oxford Crown Court.
Braim's friend, Benjamin Eyles, 19, of Marlow Bottom, Buckinghamshire, was cleared of murder but convicted of manslaughter.
The Crown Prosecution Service said the defendants had sought revenge on Mr Harling after he was said to have threatened a member of their group in Elms Park several evenings before.
Thames Valley Police (TVP) said Mr Harling was found in his upturned VW Polo just after 19:00 BST having suffered a knife wound to the chest.
Police said Mr Harling was stabbed after being involved in a brief altercation with Braim and Eyles in nearby Cotmore Close.
The victim got in his car and drove away but lost control, crashing into other vehicles, before his car overturned.
He died at the scene.
Det Insp Mike Roddy of TVP said the animosity between the defendants and Mr Harling had been "surrounding drug supply rivalries in Thame".
Senior Crown Prosecutor Kirsty O'Connor said: "Evidence in the form of a video on Snapchat and subsequent admissions from other witnesses and Eyles himself helped us prove that it was Braim who owned the knife used to kill Mr Harling.
"Our thoughts are with Joshua's family who have had to relive their pain through this trial."
Braim, of Broadwaters Avenue, was also convicted of conspiracy to cause grievous bodily harm (GBH) and carrying a weapon in a public place.
Eyles, of Monks Hollow, was also convicted of conspiracy to cause GBH.
Both will be sentenced on 26 February.