US rapper Travis Scott is facing multiple lawsuits after at least eight people were killed and hundreds injured in a crush at his Texas festival Astroworld.
One injured concertgoer has accused Scott and surprise performer Drake of inciting the crowd, and is seeking $1m (£741,000) in damages.
Neither have commented on the lawsuit.
Scott has said he is working to help the families of the victims – the youngest of whom was just 14.
The surge began at about 21:15 local time on Friday (02:15 GMT Saturday), when panic broke out as the crowd pressed towards the front of the stage during Scott’s headline set.
Lucas Naccarati told BBC Radio 5 Live that within three minutes of the rapper coming on stage, he “was pretty sure people [were] going to be dying”.
“You couldn’t move, you couldn’t scratch your own face, [that’s how] tight it was,” he said.
In a statement posted to Twitter, Houston police chief Troy Finner said he met with Mr Scott and his head of security “for a few moments” prior to the event to express his concerns about safety.
Police in the Texas city have launched an investigation into the incident and are looking into separate reports that somebody in the audience was injecting people with drugs.
Several concertgoers had to be revived with anti-drug overdose medicine, including a security officer who police said appeared to have an injection mark in his neck.
Local police declined to comment on the investigation to the BBC.
At an unrelated news conference on Monday, FBI Director Christopher Wray said that the bureau is providing “technical assistance”.
What do the lawsuits say?
On Monday, Houston-based attorney Tony Buzbee announced that his firm was failing a lawsuit on behalf of 35 plaintiffs over the “gross negligence” that led to the tragedy.
Mr Buzbee said that the lawsuit is against Scott and the event’s promoters and management, including venue and entertainment company Live Nation, for failing to implement proper security and emergency response measures.
His firm is seeking a temporary restraining order that would compel Scott and all the entities named in the lawsuit to preserve evidence, including texts and other communications regarding the event.
Among those represented by Mr Buzbee is the family of Axel Acosta, a 21-year-old from Washington state who died in the stampede.
“When [Axel] collapsed, concert goers trying to escape their own suffocation trampled over his body like a piece of trash,” Mr Buzbee said at a news conference alongside the Acosta family.
Another suit filed by 23-year-old attendee Kristian Paredes accuses Scott and Drake of inciting “a riot and violence”, and claims the venue and entertainment company Live Nation failed to provide adequate security and medical services.
The suit, seeking $1m in damages, says Mr Paredes “felt an immediate push” at the front of the general admission section, before “the crowd became chaotic and a stampede began”.
“Many begged security guards hired by Live Nation Entertainment for help, but were ignored,” it adds.
Mr Paredes is described as having suffered “severe bodily injuries”.
Scott, Live Nation and concert promoter Scoremore are also named in another suit seeking $1m in damages for Manuel Souza. Mr Souza is described as having suffered “serious bodily injuries when the uncontrolled crowd at the concert knocked him to the ground and trampled him”.
Live Nation has not yet commented on the lawsuits but has said it is “working to provide as much information and assistance as possible to the local authorities as they investigate”.
The BBC has contacted the company for comment.
High-profile US lawyer Ben Crump announced on Sunday that he was also representing concertgoers in legal action following the crush.
He filed a lawsuit on behalf of 21-year-old Noah Gutierrez and said he expected to file more for other alleged victims in the coming days. “We will be pursuing justice for all our clients who were harmed in this tragic and preventable event,” Mr Crump said.
It is not the first time that Scott has faced legal action over a concert.
In 2018, he pleaded guilty to a public disorder charge after he was accused of encouraging people to rush the stage at a concert in the US state of Arkansas. According to a local newspaper, he also paid nearly $7,000 (£5,186) to two people who said they were injured at the event.
In his first statement after the crush on Friday, Scott said he was “committed to working together with the Houston community to heal and support the families in need”.
On Monday, Scott also promised to cover the funeral expenses for the eight concert-goers who died.
Additionally, he announced a partnership with online therapy provider BetterHelp which will see the company offer one month of free therapy for anyone impacted by what took place at Astroworld.
Sense of belonging turned deadly
Angélica Casas, BBC News, Houston
A makeshift memorial has been set up along some fencing near the entrance to the festival grounds.
Ruby Ayala, 19, came to pay tribute with her family. This was Ayala’s first music festival. She went with her sister and some friends – and they made new friends among the crowd.
One of them was Franco Patino, who had travelled to Texas from out of state. He has now been confirmed as one of the eight victims.
“He had told us he would protect us because he had been to concerts like these before,” Ayala said in tears. “I thought to myself, ‘I’ll just stick with him’.”
When the commotion began, they thought it was a mosh pit, a popular dance at music events that involves people pushing against others. But then everyone around them started having trouble breathing and it was hard to get out.
They soon lost Patino in the crowd. “If I would have moved over just a little bit, that could have been me.”