Murder detectives are quizzing partygoers after a man was stabbed to death outside a 21st birthday party.

Gary Weir, 24, was at the event at Shettleston Juniors football ground and social club in the east end of Glasgow on Saturday night before the attack.

A large-scale disturbance broke out at around 12.35am on Sunday outside the party on Old Shettleston Road with three other men also seriously injured and needing hospital treatment.

Police said a 21st birthday party had been held at the club on the night in question and their priority is speaking to those who attended.

Mr Weir's death was being treated as suspicious but has now become a murder investigation after the results of a post-mortem examination.

It is understood Mr Weir was pounced on by a group of men and a large-scale disturbance ensued which resulted in him being stabbed.

He was taken to Glasgow Royal Infirmary following the disturbance but died soon after arrival.

Detective chief inspector Allan Burton from the Police Scotland's Major Investigation Team (West) said: "A murder inquiry has now been launched and extensive enquiries are being carried out by detectives to trace who is responsible.

"We are prioritising the interviewing of those who were at Shettleston Juniors on Saturday night as well as reviewing CCTV footage from the area.

"Detectives will be carrying out door to door enquiries to gather more information on the circumstances surrounding this incident.

"I would appeal to anyone who attended Shettleston Juniors Club on Saturday night, or anyone who was outside around the time of the incident to come forward as they may have information that is vital to this investigation.

"Anyone with information that may assist this murder investigation should contact Police Scotland on 101.

"Alternatively Crimestoppers can be contacted on 0800 555111, where anonymity can be maintained."

Tributes have flooded in for Mr Weir who has been described as "one in a million."

Relative Mick Weir posted on Facebook: "Heart's in pieces, four years of heartbreak isn't enough for this family?

"We lost a brother and a lot of people have lost a great friend who would never walk past someone he knew without shaking hands with them. You're back with Claire brother, so rest easy."

It is understood his family are still mourning the death of his 19-year-old sister Claire in 2012.

Easthall Residents Association described Mr Weir as "one in a million", posting on Facebook: "Gary's larger-than-life personality will be sorely missed around Easthall, he was always full of fun, making people laugh, never walked passed anyone without a handshake.

"You are one in a million, one of life's good guys. Our thoughts go out to Maggie, Paul, Paul Jnr, Mick, James and the rest of Gary's family and friends."