Nigeria Police in southern Delta state said they killed one suspect and arrested two others accused of involvement in the kidnapping last month of four Britons.
Three of the British hostages, Alanna Carson, David Donovan and Shirley Donovan were taken by gunmen on October 13 and were released earlier this week after negotiations, but a fourth, Ian Squire was killed.
Delta state police spokesman Andrew Aniamaka said officers arrested two suspects and killed a third after he opened fire, wounding two officers.
Aniamaka said two other suspects who were arrested previously led police to the three men.
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According to reports, Dr and Mrs Donovan have lived in Nigeria for the past 14 years, running a charity called New Foundations, which gave aid to remote villages in the Niger Delta.
Ian Squire, 56, was one of four British charity workers kidnapped from the rural community of Enekorogha in the early hours of 13 October.
An optician from Shepperton in Surrey, he had been working with the Christian health charity New Foundations to train local people to carry out sight tests and dispense prescription spectacles.
He had developed a solar-powered, portable lens-grinding machine for the clinic, which is located in an area without mains electricity.
Squire’s death was confirmed by the UK Foreign Office (FCO) on Monday as it announced the release of his three compatriots: the New Foundations founder, David Donovan, a GP from Cambridge; Donovan’s wife, Shirley; and Alanna Carson, an optometrist from Leven, Fife.
The circumstances surrounding Squire’s death is yet to be established.
An FCO spokesman said: “We are supporting the families of four British people who were abducted on 13 October in Nigeria, one of whom was tragically killed.