Officers are appealing for witnesses after a man was injured following an argument in Boston.
It happened in Tunnard Street at about 23.00 on Saturday night.
A man in his 20's was taken to hospital and two men and a woman are in custody.
Former East Coast Main Line rail bosses will face questions from an influential groups of MPs this afternoon, as they look to find out why the franchise failed.
Rail services on the East Coast Main Line, which runs through Lincolnshire, were put back into government control after Stagecoach and Virgin Trains ended their contract early.
Those being questioned by the transport committee include the chief executive of the Stagecoach Group.
Latest news, weather, sport and travel from across Lincolnshire.
Read MoreIt's feared livestock farmers in Lincolnshire could be facing a winter food supply crisis.
The National Farmers Union say grass isn't growing because of the weather, and farmers are having to use up food stocks meant for the winter.
Arable farmers are now being urged to bail up straw after harvesting - to help feed livestock in the colder months.
Former East Coast Main Line rail bosses and government officials face questions from an influential group of MPs this afternoon, as they try to find out why the franchise failed.
Rail services on the East Coast Main Line were put back into government control after Stage Coach and Virgin trains ended their contract early.
The chief executive of the Stagecoach Group is among those being questioned by the Transport Committee, external later.
A 24-year-old man is due in court this morning charged with the murder of Raymond Ward, whose body was found in a disused building in Scunthorpe last week.
Image source, GoogleDion Levi Hendy, of no fixed abode, is due to appear before Grimsby Magistrates.
Police are continuing to question a 47-year-old as part of their investigation.