PARKLAND, FL (CBSNewYork) – Frantic dispatch and 911 calls have been released on the deadly high school shooting in Parkland, Florida.

As CBS2’s Andrea Grymes reports, they reveal the chilling 78-minute search for the shooter, which started as a possible call about kids and fireworks.

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“Could be firecrackers. I think we got shots fired, possible shots fired – 1200 building,” Broward County Sheriff’s Deputy Scot Peterson can be heard saying.

This is the first we’re hearing of the tense transmissions between law enforcement officers responding to Marjory Stoneman Douglas High School on Valentine’s Day.

“We don’t have any description yet, we just hear shots – what appear to be shots fired,” Peterson said.

Several other members of the Broward County Sheriff’s Office can also be heard on the newly released transmissions.

Broward County Sheriff’s Deputy: “I hear shots fired by the football field, shots fired by the football field.”

Dispatcher: “Shots fired by the football field, heard.”

Admitted shooter Nikolas Cruz unleashed terror on students and staff.

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Broward County Sheriff’s Deputy: “I got a victim with a gunshot to the right leg. I got a gunshot to the right leg. Show me the west end of the high school by the football field.”

Transmissions include talk of shots fired at the field and inside the school.

Broward County Sheriff’s Deputy: “Does he know where the shooter is?”

Unknown Broward County Sheriff’s Unit: “We don’t know but we’re heading in the building. In front of the 13 building, building 13.”

Broward County Sheriff’s Deputy: “Victim saying it’s a male in a hoodie. He could not describe. With at least an AR-15, if not an AK-47.”

Also released Thursday was a sampling of 911 calls from the Broward County Sheriff’s Office.

“My son is in Stoneman Douglas High School. He says he heard noises in class and he thinks there’s a shooting going on at the school,” one caller said.

The Broward County Sheriff’s Office and the Coral Springs Police Department received more than 150 911 calls during the incident.

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Peterson was suspended and later resigned for not going into the school and confronting the shooter. He defended his actions, saying he thought shots were coming from outside the building.