A HUDDERSFIELD detective is amazed it took police in Northern Ireland so long to convict serial child killer Robert Black of his fourth murder.

The notorious Scottish paedophile was found guilty of kidnapping and murdering nine-year-old Jennifer Cardy in Northern Ireland 30 years ago.

He was jailed for life again yesterday.

In 1994, Black was convicted of three unsolved child murders in the 1980s – 11-year-old Susan Maxwell, from the Scottish Borders, five-year-old Caroline Hogg, from Edinburgh, and Sarah Harper, 10, from Morley, near Leeds – and a failed abduction bid in Nottingham in 1988.

John Stainthorpe, who was Huddersfield’s longest-serving detective, was one of the investigation team that led to Black being convicted of the brutal Sarah Harper murder.

And he is concerned that it has taken so long to bring Black to justice in Northern Ireland.

Mr Stainthorpe said: “When we were hunting Black we did a search of his work records as a driver and were able to track him all over the country.

“We had ferry records and fuel receipts to show that he was in Northern Ireland when this girl went missing.

“It put Black in the right place for the murders so I cannot understand why it has taken more than 20 years to bring him to court for this crime..’’

The jury in Northern Ireland returned its verdict at Armagh Crown Court on the second day of deliberation.

The schoolgirl was snatched as she cycled to a friend’s house in the quiet Co Antrim village of Ballinderry on August 12, 1981.

Her body was found six days later in a dam behind a roadside layby 15 miles away at Hillsborough, Co Down.

Detectives investigating Jennifer Cardy’s murder trawled 560,000 old fuel receipts and also proved he was in Northern Ireland at the time.

The receipt was found among reams and reams of microfiche retrieved from storage warehouses at the UK headquarters of Shell UK in Greater Manchester.

Black’s killing was finally ended in 1990 when he was caught with a six-year-old girl hooded, bound, gagged and stuffed in a sleeping bag in the back of his van in the Scottish village of Stow. He had sexually assaulted her moments earlier.

But Mr Stainthorpe and other senior police officers believe Black could be responsible for missing 13-year-old Genette Tate who was last seen in a country lane in Aylesbeare, Devon, in 1978. No trace of the newspaper delivery girl has ever been found.