Police received reports the man had suffered serious injuries at a property in Cygnet Court at 1.10am on Monday 20 December.
He was pronounced dead at the scene.
Lincolnshire Police is linking the incident with another serious assault in which a 46-year-old man also suffered serious injuries.
He was taken to hospital, where he remains. That incident was reported at 12.26am on Monday, December 20 and happened at an address in Bowditch Road.
A 45-year-old man has been arrested in connection with both incidents and remains in custody.
He will be questioned in due course.
Anyone with information is being urged to contact police by calling 101, or by contacting Crimestoppers anonymously on 0800 555 111 or online at crimestoppers-uk.org.