Nigel Jackson, 59, a British expat accused of murdering his wife in Portugal has written a letter for jail explaining how he believes she died . A British expat accused of murdering his wife in Portugal has admitted burying her body in the garden but denies killing her, claiming she must have died during a bungled burglary. Nigel Jackson, 59, was arrested at his country home in Alvor, near Portimao in the Algarve, in January, after the body of his wife Brenda Davidson, 72, was found in a shallow grave outside. At the time Jackson claimed Mrs Davidson committed suicide after being diagnosed with ovarian and thyroid cancer. But after being shown evidence she was killed, he had now changed his story. In a letter from jail entitled 'LOVE, CARE DEVOTION AND BETRAYAL', seen by the Daily Mirror, Jackson said Mrs Davidson must have been killed by intruders. However, he sticks to the rest of his original story, saying he buried her in his garden with their beloved pets, which they called 'babies', because he thought it's what she would have wanted. He wrote: 'As I thought it was her choice I honoured her choice that night to bury her with our babies. 'I told everyone she had gone away...this was the only lie I told and I could not live with this lie so I went to the consulate and asked them to get the police.' He described the moment he found his wife's body in a pool of blood, claiming to have held the corpse for hours begging her to wake up before discovering the knife and a wound on her neck. Jackson is accused of murdering his wife at his home in Alvor, in the Algarve (pictured). At the time he denied causing her death, saying she had killed herself, but now says she died during a burglary . He also admits to moving his mistress of three years into the house as Mrs Davidson's body lay in the garden, but said the affair was no secret. He maintains that after her cancer diagnosis his wife had acknowledged that he still had needs to fulfill, and had given her blessing, provided he didn't 'bring it home'. Jackson said he moved his partner into the house in an attempt to get over his wife's death, adding: 'I was trying to move on but I could not do so.' Jackson was initially arrested in January this year after Mrs Davidson's son Dean became concerned about her whereabouts. According to neighbours, Jackson had initially said she had returned to the UK 'for treatment for a nasty cough.' But when she failed to return to their home  Jackson then alerted the authorities and told them he was 'dedicated himself to trying to find her.' However her son eventually contacted police and Jackson was arrested at their home and questioned by police for several hours. Mrs Davidson's body was found in the garden of her home in Alvor (pictured), buried in shallow grave, while Jackson had moved his mistress into the main house . It was then that he revealed the location of the body of Mrs Davidson, his wife of 27 years. Police believe she died last November before the body was wrapped in plastic sheeting and placed underneath a concrete slab and bricks in the garden. The couple moved to the Algarve around 10 years ago from their home in Rochester, Kent and had built up a close set of friends in the close-knit village. They had apparently got bored of their life in Kent and Mr Jackson, a former taxi driver, and his wife, a retired cleaner, moved to Portugal for a change of scene. Sorry we are not currently accepting comments on this article.
Nigel Jackson, 59, arrested at property in Algarve, Portugal, in January .
Body of wife Brenda Davidson, 72, found in shallow grave in the garden .
Jackson initially claimed she killed herself, but he has now changed story .
Shown proof she was killed, he now says she must have died in burglary .