PHILADELPHIA (WPVI) -- More questions are being raised following the deadly surge of people that stormed the stage at a Houston concert over the weekend.
Eight were killed, including two teens, and several others were seriously injured during Travis Scott's performance at the Astroworld Festival.
At least one lawsuit has been filed against the rapper and concert promoter giant Live Nation.
Law enforcement experts following the case said, unfortunately, this is a case that won't come with quick answers.
"Hopefully, they follow the model of the NTSB, in which they look at it from every potential aspect in how to prevent something like that from happening," said security expert and retired Philadelphia Police Deputy Commissioner Joe Sullivan.
Sullivan said there will likely be three parts to the investigation: criminal, civil, and regulatory violations.
"It'll begin with the review of the emergency plans to determine who drafted them, who approved them and were they sufficient for a venue of this size," Sullivan said.
ABC News obtained a copy of Astroworld's medical plan, but experts say it only works if communication and contingency plans are in place when things go wrong.
Another question legal experts say will come up: were there overall staff shortages related to COVID-19?
"That's ripe for litigation. That's ripe for them being held civilly liable," said Texas legal expert and attorney Shaun Naidoo.
Naidoo said one thing that is pretty clear: the potential for damages here against Scott and concert promoters is high.
"We're looking at millions of dollars of judgment and potential liability for Travis Scott and his people," Naidoo said.
Problems have previously occurred at other Travis Scott concerts. In 2015, the rapper was arrested on charges of inciting a crowd to jump barriers at a Lollapalooza concert in Chicago. He pleaded guilty to disorderly conduct and paid a fine, according to officials.
In 2017, Scott was arrested again after he invited more people to come closer to the stage, prompting fans at the Walmart Music Pavilion in Rogers, Arkansas, to breach barricades and overrun security. In that case, he also pleaded guilty to misdemeanor disorderly conduct and paid a fine.
Action News reached out to various venues in the city that host large concerts about protocols in place.
A Philadelphia Eagles spokesperson said in part, "We have numerous protocols in place that are regularly reviewed and updated."
Scott has said he will pay for the funeral costs of the eighth victims as well as pay for therapy for those affected by the festival.
-- ABC News contributed to this report.