A 15-year-old boy was arrested in the western Peloponnese on Thursday for causing the death of two schoolgirls and seriously injuring their mother with his father’s car that he had been illegally driving. The boy, whose name was not released, took the car on Thursday afternoon for a drive along the national road from Kyparissia to Pyrgos. At the village of Kakovatos, near Zaharo, he suddenly lost control and veered off the road into a wall before hitting a small group of two adults and two children on their way to a birthday party. Alexandra Christopoulou, 11, and her six-year old sister, Kalliopi, died instantly. Their mother, Ioanna Christopoulou, 48, was severely injured, while her friend, Ekaterini Nikolopoulou, 43, escaped with lighter injuries. The boy was taken to hospital in Pyrgos with slight injuries, and then detained in a police cell. His father was also arrested. It was not clear if the father had allowed the son to use the car. The minimum legal driving age in Greece is 18.