Lincolnshire Police are treating the death of a 29-year-old man in Ingoldmells as murder.
Officers were called to a property on Chapman Court just before 2.30am on the morning of Wednesday, December 6, after reports of a man seriously injured.
He was pronounced dead a short time later.
The man has been named locally as Gareth Bailey, with tributes being left to him on social media.
A woman in her early 20s was arrested by Lincolnshire Police on suspicion of murder and is in custody.
Police have now arrested a 39-year-old local man, also on suspicion of murder.
Detective Jim Hodgson, of EMSOU Major Crime and leading the investigation, said: “We have been carrying out a number of lines of enquiry in relation to this incident and we are now investigating this as a murder.
“I’m appealing for witnesses in relation to this enquiry and would like to hear from anyone who may have any information they think could help the investigation.”
Anyone with information should call police on 101, quoting incident 26 of December 5.
Alternatively, contact the independent charity Crimestoppers anonymously on 0800 555 111.