Three 15-year old boys have been arrested after they allegedly stole five luxury cars during a series of aggravated burglaries in the city's northwest. Police believe the three teens entered a number of houses in Maribyrnong, Airport West, Truganina and Hillside in the early hours of Sunday. Five cars were stolen, including a Porsche and two Audis, and so far only two have been recovered, police say. One victim suffered minor upper body injuries during one of the break-ins.