Two teenagers were attacked by people carrying metal bars in Ashdown Road, Reigate, on Monday, November 6.
Police were called just before 7pm to reports that the victims, a boy and a girl, were assaulted by four people.
Later that evening, just before 8pm, police were called to a car fire in Alexander Road, which they believe was deliberate.
Nobody suffered any injuries in the fire, but police believe the events are connected.
A 33-year-old woman from Reigate and a 17-year-old boy from Horley were arrested on suspicion of causing grievous bodily harm, and they remain in custody.
Surrey Police is asking that anyone with information calls 101 or visits surrey.police.uk/contact-us/report-online, quoting reference 45170123484, or call Crimestoppers anonymously on 0800 555 111.
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