Murder squad detectives investigating the death of a pensioner have identified her as 79-year-old Betty Constable from Dunholme.
Ms Constable was taken to hospital from her home in Merleswen at about 11am on Sunday.
Hospital staff raised concerns about her condition and called police at 2pm that afternoon.
Ms Constable died in hospital at 10am on Tuesday. Police carried out initial enquiries and launched a murder investigation the following day.
A 51-year-old man was arrested in the West Yorkshire area on Wednesday evening and is helping police with their enquiries.
DCI Martin Holvey said: “I can confirm that a murder investigation has been launched and I would urge anyone with any information that they think might help us to get in touch as soon as possible.
“We are not seeking any other suspects in relation to this investigation and there is no threat to the community.
“I would urge any local residents with any concerns to discuss them with our local officers in the village.”
Call Lincolnshire Police on 101, or call Crimestoppers anonymously on 0800 555 111.