HOUSTON (NewsNation Now) — Houston Police Chief Troy Finner on Wednesday refuted a story that somebody pricked a security guard’s neck, possibly injecting him with drugs, during the chaos at the deadly Travis Scott concert.

On Saturday, Finner said first responders treated the security guard with the opioid antidote Narcan after he lost consciousness.

“We did locate this security guard,” Finner said during a news conference Wednesday. “His story is not consistent with that. He says he was struck in his head. He went unconscious. He woke up in the security tent. He says that no one injected drugs in him.”

Finner also said the investigation into the surge that left eight dead and hundreds injured during the performance will “take weeks, possibly months.”

Determining an accurate timeline of events is a major focus of the investigation.

“We’re not gonna leave any stones unturned,” Finner said.

Finner offered few new details but said merchandise tents contributed to fans rushing and one of Live Nation’s roles was to secure mosh pits. He also said organizers of the festival have not provided investigators with clear records about private security personnel working the grounds.

The chief also forcefully defended his department’s ability to handle the criminal investigation on its own, rejected calls for an outside probe and said he did not have a close relationship with the megastar rapper, who is from Houston and founded the sold-out festival that drew 50,000 fans.

At least two concertgoers remained in critical condition Wednesday.