(CNN) -- [Breaking news update at 12:19 p.m. ET]
The Broward Sheriff's Office has released 27 minutes of footage from outside Marjory Stoneman Douglas High School on the afternoon of the Valentine's Day massacre. CNN is reviewing the video.
[Original story published at 10:57 a.m. ET]
Troubling questions about what happened outside Marjory Stoneman Douglas High School during last month's massacre may be answered Thursday.
Several media organizations, including CNN, sued to obtain surveillance footage at the Florida high school, where 17 people were gunned down on Valentine's Day by a former student.
A Florida judge ordered the release of the surveillance video, which could come Thursday afternoon.
Authorities have said the footage confirms that former Broward County sheriff's deputy Scot Peterson never went inside the building where Nikolas Cruz was shooting at students and school staff.
Peterson, a school resource officer at the time, was armed but stayed outside the building for four minutes, authorities said.
During that time, Peterson got on his radio and took a position where he could see the western entry of the building, Broward County Sheriff Scott Israel said. In a statement via his lawyer after the shooting, Peterson had said he wasn't sure where the shots were coming from. But in dispatch audio released recently, the school resource officer can be heard telling a dispatcher, "I think we have shots fired, possible shots fired, 1200 building."
The sheriff criticized Peterson for not confronting the gunman. The deputy was suspended without pay and he resigned shortly afterward.
The security footage expected to be released Thursday could also show whether any other officers were nearby, and what their actions were.
Immediately after the shooting, responding officers scrambled to the scene but appeared to be following commands from Peterson to close the road in front of the school and set up a perimeter.
They also were operating on delayed information. Security footage from the school had somehow been rewound, and police were watching it on a 20-minute delay -- leading them to believe the gunman was still in the building, when he was long gone.
But that mishap "never put us in a situation where any kids' lives were in danger, any teachers lives were in danger," said Coral Springs Police Chief Tony Pustizzi, whose officers responded to the scene.
Unlike the school's security footage, some 911 calls and police radio traffic audiotapes have been gradually made public.
In the past week, the Broward County Sheriff's Office and the Coral Springs Police Department released calls illustrating the fear and panic of students and parents on February 14.
Desperate parents can be heard relaying information to 911 dispatchers after exchanging text messages or speaking with their children inside the school.
And first responders could be heard trying unsuccessfully to communicate among themselves, due to equipment failures and other issues.
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