Police have named the murder victim found in Boston on Sunday as 46-year-old Marcin Stolarek.
Three people have been arrested on suspicion of murder.
Two men, aged 26 and 33, and a woman, aged 26, were arrested in Boston last night (January 15).
They remain in police custody.
Lincolnshire Police have released videos in English and Polish in the hope of receiving information.
Detective Chief Inspector Karl Whiffen, from East Midlands Special Operations Unit (EMSOU) said: “I am appealing for anyone with information about Marcin to get in touch.
“Marcin lived in Boston but also had links to Spalding, and people in those communities may have details that could prove crucial to our investigation.
“Please come forward with information so that we can bring his killer, or killers, to justice.”
Police want to hear from anyone who has seen Marcin in the last four months, or who has information that could help the investigation.
“Even the smallest detail could be vital,” a spokesman added.
Police believed Marcin died as a result of a sustained assault before offenders disposed of his body in a waterway.
If you have information, contact police in the following ways:
- Call 101, quoting Incident 313 of 12 January
- Report information online though the Major Incident Portal
- Email email@example.com putting “Incident 313 of 12 January” in the Subject line
- Contact Crimestoppers, anonymously, on 0800 555111