A MURDER investigation has been launched after a father-of-four was kicked to death in Bolton town centre as he walked home after a night out.

Witnesses described seeing two men kicking and punching what they thought was a bundle of rags on the floor in the early hours of Saturday.

But as they got closer they realised it was a man, today identified as Robert Johnston, a 39-year-old grandfather, of Levens Drive, Breightmet.

When the attackers saw the two men approaching they calmly crossed the road and walked away towards Bradshawgate.

The witnesses alerted the ambulance service and the Mr Johnston, who was unconscious, was taken to the Royal Bolton Hospital suffering from severe head injuries.

He died eight hours later.

Detectives are appealing for witnesses to the brutal attack which happened around 2.50am on Saturday morning.

Police say the man and his friend were involved in an argument with two men as they took a short cut along Saville Street, off Shiffnall Street, after a night out in Bolton.

The dispute developed and two men began kicking and punching the friends in a sustained attack.

A police patrol arrived and found the man lying unconscious on the pavement, with the two men who had called for an ambulance, shortly before 3am.

The victim's friend, 38-year-old Darren Paul O'Donaghue, of Holme Avenue, Brandlesholme, Bury, suffered facial injuries but declined hospital treatment.

Today, detectives condemned the attack as they launched a murder hunt for the killers.

Detective Inspector Mike Stanfield, said: "This is a disgraceful attack on two men who were simply making their way home after a night out in Bolton.

"From what the two witnesses have told us, the offenders were repeatedly kicking and punching the man while he lay on the ground unconscious. When they had finished they calmly crossed the road. The man suffered terrible head injuries."

A 200-metre cordon sealed off the murder scene, close to Ride 'n' Drive bike shop in Shiffnall Street, while scenes of Crime officers carried out a fingertip search of the area.

Most of the roads remained closed throughout Saturday while detectives preserved evidence at the scene.

Over the weekend devastated family and friends laid flowers at the scene.

Mr Johnston's long-term partner Sharen laid a simple bunch of red roses which stated: "To my darling Rob. You were my world and now you've been taken away from me. I love you and will for the rest of my life. You were my life."

There were many more messages from brothers and sisters, his four children and his two grandchildren Leonni and Morgan which read: "We only knew you for a short while but will miss you loads."

Today at the family home relatives were too upset to speak.

Anyone with information is asked to contact murder squad officers at Castle Street police station, Bolton on 0161 856 5965 or Crimestoppers anonymously on 0800 555 111.