Five victims of death crash were all in car stolen just hours before
His condition is not said to be life-threatening.
None of the dead are believed to have been wearing seatbelts when the car careered off a leafy suburban street in the Meanwood area of Leeds on Saturday night.
Another 15-year-old, arrested in the vicinity of the crash, has been released. Police initially believed all seven males had been in the car.
Yesterday Det Chief Insp Jim Griffiths said: “When I arrived here in the early hours of Sunday morning this was a catastrophic scene.”
Those attending, he added, witnessed “a scene of total carnage”.
People living nearby described bodies lying in the road and a car reduced to a mangled wreck.
Mr Griffiths said the vehicle had been stolen from outside a home in the Headingley area of Leeds at 6.30pm on Saturday and driven for hours.
Relatives of the brothers were among a succession of people who went to look at the growing shrine of flowers, balloons, candles and messages at the scene in Stonegate Road.
Debbie Harrower, who used to babysit Ellis and Elliott, said: “They were little terrors, but they were good boys. It’s just sad.”
Earlier, a woman understood to be the mother of one of the victims arrived at the scene sobbing “my son”.
She stood next to the tree, now surrounded by floral tributes, staring at the scene.