A man died from assault injuries along the Grand Union Canal near Broughton on Monday (26/4). He has been named as Cliver Porter, aged 63 from Tring.
Two arrests have been made in connection with this investigation.
A 34-year-old man of no fixed abode has been arrested on suspicion of murder.
He has been receiving hospital treatment while in custody.
A 41-year-old woman from Birmingham has been arrested on suspicion of assisting an offender and perverting the course of justice.
The woman has been released on police bail until 24 May.