The 21-year-old man died despite the efforts of emergency services called to the scene at a house in Portland Street.
Lincolnshire Police say the man, who has not yet been named, was found with serious stab wounds yesterday (Wednesday July 14).
They were called to the scene after reports were received at around 12.13pm that a man had received a serious stab wound.
A woman in her 20s has been arrested on suspicion of murder and she remains in police custody.
Investigations are currently ongoing.
Detective Chief Inspector Richard Myszczyszyn from East Midlands Special Operations Unit said: “We are appealing for anyone with any information, no matter how small, to please come forward and get in touch with us.
“If you have any information that can assist with our investigation, please call 101 quoting incident 169 of today’s date.”
There are a number of ways that you can get in touch and police are particularly keen to speak to anyone who might have video footage.
A spokesperson for the force said: “We would specifically like to speak to anyone who was in Portland Street on 14th July 2021 between 11:00 and 13:00 who may have recorded footage of the street.
“This could be dashcam, mobile phone footage, CCTV or Ring doorbell. We would also like to speak to anyone who has information that could be relevant to the enquiry.”
Information can now be reported and footage sent via a dedicated portal set up by police for the incident at https://mipp.police.uk/operation/33EM21C77-PO1
Anyone who can help can also call 101 quoting incident 169 of 14th July, emailing [email protected] –using incident 169 of 14 July in the subject line, or remain anonymously via the independent charity, CrimeStoppers on 0800 555 111.