A 15-year-old suffered serious injuries when the car he was in, driven by a 17-year-old, crashed into a wall in Ta' Qali.
The police said the incident took place at 11.15pm on Friday near the dog park.
It transpired that the 17-year-old lost control of the Renault Zoe that he was driving and crashed into a wall.
Apart from the injured 15-year-old, there were three others in the car: two boys aged 15 and 16, and a 17-year-old girl.
Magisterial and police investigations are ongoing.