DJ and producer Inga Mauer was subject to an attack by security at Flow Festival in Helsinki, Finland on Saturday (August 12).
Mauer, who played earlier in the day, was later arrested by police and spent a night in jail.
Organisers of the festival say they have got video footage and photo evidence of the incident with the security team, while artist Marie Davidson has given a detailed account of what happened.
As reported by RA, Davidson said: "I witnessed a bunch of security guys hold a girl on the ground while she was screaming. As I approached to try to help, I found out that this girl was actually my friend Inga Mauer, an artist who had played a killer set only two hours before. She said they violently dragged her out of the festival area because she refused to leave right away.
"I tried to interfere and explain that I knew her and that I wanted to help her calm down because she was extremely confused and scared. As a result, we got both put aside, in a corner, isolated from the rest of the crowd. I tried to reach out to my friend but they wouldn't let me touch her."
Davidson, who stated the two artists were "actually sober", went on to describe how Mauer "was bleeding from her knee" after the incident. Davidson herself was removed from the festival site.
She said: "Two security guys took me by the arms and threw me out in the street out of the festival zone. I told them I needed to at least be in touch with someone because I had no internet, no driver and no taxis were taking people to any place at this hour.
"They laughed and said 'go figure it out' and then closed the fence, leaving me in a totally unknown place without any way of reaching out for help. I had to ask strangers in the street to help me find a taxi to my hotel. About an hour after, I was back to my room, learning that my friend would spend the night in jail, to be released in the morning."
In a statement, Flow Festival has called out security company Local Crew Oy for failing "to do their job in the right manner."
The organisers also apologised to the artists for the violence they encountered.
"It came to our knowledge that members of the security staff had used violence against Inga Mauer. Marie Davidson, who approached to try to help her, was inappropriately thrown out of the festival area.
"Even the police who came to sort out the situation acted threateningly and refused to give us any information after taking Inga Mauer to jail overnight. Flow Festival does not approve the use of violence and we were shocked and very sad to hear this. We are truly sorry for what Inga Mauer and Marie Davidson had to go through."
Flow Festival took place from August 11 to 13 and featured Aphex Twin, Willow, Maceo Plex and Nina Kraviz.
Dave Turner is Mixmag's Digital News Editor, follow him on Twitter