At least eight people died and about 300 were injured Friday in rapper Travis Scott's concert in Houston. Police said Saturday that they are investigating claims of multiple concertgoers being involuntarily injected with a drug.

“This is now a criminal investigation that’s going to involve our homicide division as well as narcotics, and we’re going to get down to the bottom of it,” Houston Police Chief Troy Finner said at a news conference.

Harris County Judge Lina Hidalgo called for an "objective, independent investigation as to what went on and how it could have been prevented." Houston Mayor Sylvester Turner said the investigations could last days or weeks or “even longer.”

Around 50,000 people attended the Astroworld Festival at NRG Park. Questions surround the level of security and medical personnel for such a large event.

Officials say that around 300 people were treated for injuries like cuts and bruises from being crushed, along with several people needing “anti-drug” overdose medicine.

A security officer may have been drugged after he felt a “prick in his neck.”

"We do have a report of a security officer... that he was reaching over to restrain or grab a citizen and he felt a prick in his neck," Finner said.

"When he was examined, he went unconscious," Finner said. "He was revived, and the medical staff did notice a prick that was similar to a prick that you would get if somebody is trying to inject."

The mother of one male victim told the Washington Post that she was told by authorities that her son’s “heart stopped” after he was crushed by the crowd.

Those who died include Brianna Rodriguez, 16; Danish Baig, 27; Franco Patino, 21; Rudy Pena, whose age has not yet been confirmed. Others include a 14-year-old, another 21-year-old, and two 23-year-olds.

Scott posted on Twitter Saturday, “I’m absolutely devastated by what took place last night. My prayers go out to the families and all those impacted by what happened at Astroworld Festival.”

“I am committed to working together with the Houston community to heal and support the families in need. Thank you to Houston PD, Fire Department and NRG Park for their immediate response and support. Love You All,” he added.