Three men were released under investigation after a 37-year-old man was seriously assaulted in Grantham.
The man was injured after an incident at a property near Nationwide Building Society on High Street in Grantham on the afternoon of Friday, April 26.
Three men were arrested in connection with his incident, but officers are keeping an open mind about what has happened, police said.
Two of the arrested men are in their 40s and the other is in his 50s. Lincolnshire Police confirmed on Sunday, April 28 that the three men were released under investigation.
Lincolnshire Police are appealing for information and want anyone with CCTV covering the area, or Elmer Street South, between 11am and 10pm on April 26 to get in touch.
Police would also like to hear from people who saw or heard anything unusual that afternoon including anyone with unexplained injuries.
Anyone with information or dashcam footage should contact police on 101 quoting incident 490 of April 26.