In an excerpt, Schiller is heard calling out saying that people need to call 9-1-1. 

“We don’t know if there’s a shooter — active shooter, active shooter somewhere,” Schiller said in the video. 

Schiller is heard on the video asking what appears to be a store employee whether a shooter went into the store.

Here's how that conversation played out:

"Yeah, he went in there," the man responded.

“He went in the store?” Schiller asked.

“He went right down there,” the man responds. 

“Oh my god,” Schiller reacts. “People we got people down inside Kings Soopers.”

Schiller then says, “Look there’s-,” but doesn’t finish his sentence as two gunshots stop his speaking.

Some background: Boulder Police had tweeted earlier on Monday there was an, “Active Shooter at the King Soopers on Table Mesa. AVOID THE AREA.”

Helicopter footage shows a shirtless man being taken from the supermarket. The man had what appears to be blood on his arm and right leg and his hands appeared to be cuffed behind him as two officers escorted him away. The man was taken away in an ambulance.

Shooting witness says some people ran, others froze

Ryan Borowski, one of the people inside the King Soopers grocery store when a shooter starting firing shots, said everyone helped each other get out of the back of the store.

He said he heard two loud sounds, and by the third one, he and the people around him realized they were gunshots. He said they started running to the back of the store and employees helped them out the back door.

"We told employees what was going on so everybody helped each other and we just ran to safety as quickly as we could," Borowski told CNN from behind the store in Boulder, Colorado, about two hours after the shooting.

Borowski said he was going to get ice cream, but then changed his mind and started walking the other way.

"I didn't see the shooter. I saw terrified faces running towards me and that's when I turned and ran the other direction," he said.

He said everyone was helping each other, but while some people ran, others froze.

"We ran and I don't know why other people didn't and I am sorry that they froze and I just wish that this didn't happen – I wish I had an answer for why it did," he said.

He said he could have never imagined a situation like this happening in Boulder.

"Boulder feels like a bubble and the bubble burst and that's heartbreaking. To think that people died today," Borowski said. Police have not confirmed whether anyone was killed.

"This feels like the safest spot in America and I just nearly got killed for getting a soda, you know, and a bag of chips. Doesn't feel good," he added.

The FBI is on scene to assist Boulder police

FBI Denver personnel are on scene helping the Boulder Police Department, according to a tweet.

“At the request of the Boulder Police Department, FBI Denver personnel are assisting with an investigation into an active shooter situation at a King Soopers grocery store on Table Mesa Drive in Boulder,” the agency tweeted.

CNN’s Lucy Kafanov reported seeing FBI agents on the scene at the supermarket.

Man says his family members hid inside a closet for an hour

CNN affiliate KCNC reporter Conor McCue spoke with a man whose family was inside the King Soopers pharmacy to get a Covid-19 vaccine when the shooter arrived. He said they hid in a closet for an hour before being rescued through the roof.

"I got the call from my daughter and my grandchildren that my son-in-law walked into the pharmacy for him to get a Covid-19 shot and the shooter came in, shot the woman in front of them," the man told KCNC.

"They hid, ran upstairs, were hiding in a coat closet for the last hour," he said. "They are okay. They just are now out the back," he added.

He said his daughter was texting him from the closet, before turning her phone off.

"They were texting, hiding in the coat closet. Turned their phone off and were going ‘we’re hiding, we’re okay’ you know, ‘don't call’ you know the phone would ring and give away their position," he said.