The family of a man whose body was found in a canal have said they "will never understand why someone would want to hurt him".
The body of Scott Anderton, 33, was found in the Leeds and Liverpool Canal near King Street, Leigh on Thursday.
He died after suffering stab wounds and blunt trauma, police said.
Two boys, aged 16 and 17, and an 18-year-old man, who were held on suspicion of murder, have had their time in custody extended.
In a tribute, Mr Anderton's family said: "As you can imagine our family are still struggling to come to terms with what has happened and will never understand why someone would want to hurt Scott."
"Even on the darkest of days, Scott was always positive and had the cheekiest smile, which was infectious," they added.
"Our family have been robbed of a son, dad, grandson, brother, nephew and uncle.
"You will forever be our diamond in the mud."
Greater Manchester Police are appealing for anyone with information to contact them.
A 21-year-old man, who was previously arrested on suspicion of murder, has since been released with no further action.