A festivalgoer stabbed at the T In The Park festival in Scotland was attacked after coming to the aid of a female friend.
Tayside police said a 22-year-old man suffered multiple wounds when he was attacked in the yellow zone of the festival's campsite in the early hours of Sunday morning.
The victim is said to be making "good progress" in the intensive care unit at Ninewells Hospital in Dundee after being stabbed a total of 11 times - eight in the body and three in the head.
Det Ch Insp Bruce Kerr, from Tayside Police, told BBC Radio's Good Morning Scotland programme: "He was an innocent victim.
"He went to intervene with the two males who were accosting one of his female friends and they just set about him and he was stabbed 11 times, eight to the body and three to the head."
The site was cordoned off and a forensic examination took place after the incident while detectives said they were searching for two men, who are likely to be wearing blood-stained clothing.
The first man was described as white, about 6ft 1in tall, of skinny build with short, dark brown hair. Police said he was wearing a white tracksuit top at the time.
The second suspect is said to be white, about 5ft 8in tall, of medium build and with short, dark brown "mullet-style" hair. He was seen in a red tracksuit top during the attack.
Amy Winehouse, REM, the Hoosiers and the Prodigy performed at the three-day festival's final day on Sunday.
Music fans saw over 150 acts including The Verve, Kaiser Chiefs, Chemical Brothers and Interpol at the festival which started on Friday.
Festival director Geoff Ellis commented: "In T in the Park's 15-year history this is the first time we have had a stabbing on-site and we are shocked and saddened to hear the news. Our thoughts are with the family at this time.
"[The stabbing] was isolated, but serious. Fortunately we have a great medical team and a medical hospital on site and we were able to treat him very quickly and he's in a stable condition.
"Hopefully the police will catch the people responsible."