Four men have been arrested in Enfield on suspicion of kidnapping and causing grievous bodily harm.
The four were stopped in a black BMW 1 series on Friday evening.
They have been arrested on suspicion of kidnapping a 15-year-old boy in south east London between 3pm and 4pm, in an attack in which the youth was seriously assaulted by two white and two black men believed to be in their 20s.
The teenager’s injuries and not thought to be life threatening.
Police enquiries continue.