A 55-year-old man has been arrested on suspicion of the murder of a mother of six who was found unconscious after taking her dog for a walk.

Anita Rose left her house to take her springer spaniel Bruce for a walk at around 5am on July 24.

The 57-year-old was found at about 6.25am lying unconscious on a track road near the sewage works and railway line off Rectory Lane in Brantham, Suffolk, by a male cyclist who called an ambulance.

With her jacket taken, she was found wearing only her bra on her top half, as well as leggings and trainers on her lower half, with Bruce’s lead wrapped around her leg, Suffolk Police said.

The dog was not harmed.

Ms Rose was taken to hospital and died four days later.

Police arrested a 55-year-old man in Ipswich on suspicion of murder on Monday morning, the force said.

The man is currently being questioned at Martlesham Police Investigation Centre.

Previously, there have been three arrests in connection with the inquiry – a man aged in his 20s and a 45-year-old man on suspicion of murder, and a 37-year-old woman on suspicion of handling stolen goods.

All three were subsequently released on bail.

Last month, Suffolk Police released CCTV images of two potential witnesses that officers would like to speak to, and stressed that the pair are not suspects in the case but that officers believe they may be able to assist with inquiries.

One of them has now been identified and is assisting officers with inquiries, the force said, and police are continuing to try to identify the second person.

The independent charity Crimestoppers has offered a £20,000 reward for information that leads to the arrest and conviction of anybody involved in the death of Ms Rose.

Anyone with any information that may assist with the inquiry is asked to contact the Major Investigation Team via the online portal at https://mipp.police.uk/operation/363723O47-PO1

Alternatively, they can contact the independent charity Crimestoppers on 0800 555 111 or via its online form at www.crimestoppers-uk.org