During the deadly mass shooting at the Marjory Stoneman Douglas High School in Parkland, Florida last week, in which 17 people were gunned down, it has been revealed that a critical disconnect confused responding police and hindered their capture of the gunman.

Police officers watching surveillance video of the incident thought the video was live, and then later discovered it was on a 20-minute delay. What they were watching on the video had already happened, and the gunman had already left the scene.

“The Broward School District’s security cameras did not provide real-time video for police during the Stoneman Douglas school shooting. An outdated radio system provided further confusion as officers tried to find Nikolas Cruz,” the Sun-Sentinel reported.

Fox News reported:

“[Video images were] delayed 20 minutes and nobody told us that,” Coral Springs Police Chief Tony Pustizzi told the Sun Sentinel.

Cruz walked into the campus’ freshman building around 2:21 p.m. and began firing at students and staff, killing 17 people, police said. He left the school seven minutes later, blending in with terrified students.

Responding officers were heard on radio transmissions at 2:54 p.m. saying they were seeing Cruz on camera going from the third to the second floor. By that time, Cruz had been out of the building for 26 minutes, according to the newspaper.

“He went from the third floor to the second floor…They’re monitoring him on camera,” an officer was heard saying on the radio transmission released by Broadcastify.

Pustizzi recalled officers attempting to pinpoint Cruz when the shooter wasn’t even in the building.

“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 said.

On a radio transmission from the day of the shooting, an officer finally said, “It’s about a 20-minute delay, they’re following him on video, on the camera…They have him exiting the building, running south.”