A 71-year-old man has been arrested in Pakistan in connection with the murder of Pc Sharon Beshenivsky, who was shot while on duty in 2005.
West Yorkshire Police said Piran Ditta Khan was held on Tuesday following an operation involving the National Crime Agency and local partners.
He appeared in an Islamabad court on Wednesday, where his extradition was discussed.
Khan was remanded in custody to next appear at court on January 29.
Pc Beshenivsky was shot while responding to a robbery at Universal Travel in Morley Street, Bradford, on November 18 2005.
Detective Superintendent Mark Swift said:
I would like to thank the National Crime Agency officers in Pakistan and partners who have made this arrest possible.
Pc Beshenivsky was a 38-year-old married mother of three with two stepchildren, and was a probationer with only nine months' service when she was killed.
Her colleague, Pc Teresa Milburn, was also shot but survived to later give evidence at the trial of members of the armed gang who were charged with being involved in the murder.
Six men were later jailed at Newcastle Crown Court, but Khan, a former bouncer who was suspected of being the gang organiser, had fled abroad.
In 2016, West Yorkshire Police issued a fresh appeal for find him as he remained at large despite a £20,000 reward for information leading to his arrest.
The case has gone on for over a decade and Widower Paul Beshenivsky says he wants closure:
West Yorkshire Police Federation said officers were delighted at the breakthrough.
Federation chairman Brian Booth said:
The persistence to capture and bring to justice all those involved in the murder of Pc Sharon Beshenivsky has to be applauded.
A memorial marks the spot where Pc Beshenivsky was shot at close range outside the travel agents.
The UK's High Commissioner to Pakistan said "a tremendous amount of work" had gone on behind the scenes with local organisations and the British police.
Christian Turner said:
Teams at the British High Commission in Islamabad, West Yorkshire Constabulary, and our partners in Pakistan, have worked together to make this possible.