(CNN) -- Surveillance footage from the Florida high school where 17 people were gunned down was not live, as responding officers initially thought -- it was actually on tape delay, the Sun Sentinel newspaper reported.
The video images were "delayed 20 minutes, and nobody told us that," Coral Springs police Chief Tony Pustizzi told the Sun Sentinel.
But Coral Springs police Capt. Brad McKeone, one of the responding officers, said the tape delay did not hinder the police response to the victims.
"It had no delay. It didn't slow us down to getting us to anybody," McKeone told CNN.
The main difference, McKeone said, was that officers thought they were going to confront the gunman. In reality, the shooter had already left Marjory Stoneman Douglas High School in Parkland.
"I expected to be in a gunbattle," McKeone said.
Broward County Public Schools has not responded to CNN's request for comment Thursday about the school surveillance system. The Broward County Sheriff's Office, which is now leading the shooting investigation, also has not explained why the video was on tape delay.
Gunman was already at Walmart
While the tape delay might not have increased the number of casualties, it did hamper efforts in locating the gunman.
McKeone told CNN about 20 to 25 officers were on the first, second and third floors of the school when they thought the shooter was still inside.
"Somebody would say, 'He's on the second floor,' and we had guys on the second floor saying, 'We're on the second floor, we don't see him.' That's when we figured out there's a tape delay," Pustizzi told the Sun Sentinel.
Police scanner traffic from the streaming website Broadcastify detailed what police thought was happening at 2:54 p.m. on February 14:
"They are monitoring the subject right now," one person says. "He went from the third floor to the second floor. He may have a gas mask on now. Stand by for further. They're monitoring him on camera."
But according to a timeline provided by the Broward County Sheriff's Office, the suspect purchased a drink at a Subway restaurant inside a Walmart store at 2:50 p.m. -- four minutes before the scanner traffic said the gunman was still on the second floor of the school.
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