The boy was riding a bike that collided with another vehicle in the Edenmore Road area of Limavady.
Darren McGurk died four days after he suffered a head injury in an attack in County Londonderry.
The man has suffered a serious head injury in the assault which took place in the Glenbeg Walk area
Sentimental jewellery which was stolen from Limavady 10 years ago is found in Newry.
The boys aged 15 and 16 rare being questioned by police