Three people have been arrested on suspicion of murder after a body was found in Boston.
Police believe the victim is 46 year old Polish national Marcin Stolarek, whose body was found at the pumping station on Sunday.
Officers announced two days later that the investigation into his death was being treated as a murder enquiry.
Lincolnshire Police have today revealed that two men, aged 26 and 33, and a woman aged 26, were arrested in the town last night.
They remain in police custody.
It is believed Marcin may have died as a result of a sustained assault before his body was dumped in the water.