The ashes of serial child killer and sex offender Robert Black have been scattered at sea.

Black, who was serving multiple sentences for the murders of four schoolgirls during the 1980s, died in jail last month.

The Northern Ireland Prison Service confirmed nobody wanted his remains.

A spokesman said: "In the absence of anyone claiming the remains of Robert Black, his ashes have been scattered at sea, without ceremony, beyond these shores.

"This has been done in accordance with the legal requirements for disposal."

Black, 68, from Falkirk, was a delivery driver who stalked the roads of the UK searching for victims.

His murder spree ended in 1990 when he was caught by police with a barely alive six-year-old girl hooded, bound, gagged and stuffed in a sleeping bag in the back of his van in the village of Stow in the Scottish Borders. He had sexually assaulted her moments earlier.

Once in custody, the predator was linked to a series of unsolved crimes in the previous decade.

In 1994, Black was found guilty of three child murders in the 1980s - those of 11-year-old Susan Maxwell, from the Borders, five-year-old Caroline Hogg, from Edinburgh, and Sarah Harper, 10, from Morley, Leeds - as well as a failed abduction bid in Nottingham in 1988.

In 2011, he was found guilty of the 1981 murder of nine-year-old Jennifer Cardy, from Ballinderry, Co Antrim.

Black was also suspected of involvement in other killings and unexplained disappearances and had long been the prime suspect in the case of missing 13-year-old Genette Tate, who was last seen in a rural lane in Aylesbeare, Devon, in 1978.

No trace of the newspaper delivery girl has ever been found. All that remained at the scene were scattered papers and her bike.

Black died in non-suspicious circumstances in Maghaberry high security prison on January 12 and his body was cremated.

No family members attended the short funeral service, which was conducted by a prison chaplain.