Nearly 140 bullets flew again at Marjory Stoneman Douglas High School in Parkland, Florida on Friday — as experts re-enacted some of the horrors of the 2018 massacre that killed 17 and wounded just as many.

The chilling reenactment was part of a lawsuit against Scot Peterson, the former sheriff’s deputy accused of failing to protect students and staff during the six-minute carnage.

Peterson, who was armed at the time, has claimed he only failed to rush in and help because he had no idea where the gunshots were coming from, which some of the victims’ families aim to prove was impossible.

From noon Friday, technicians outside recorded the sounds of 139 bullets being fired inside the three-story school building to capture what the then-deputy likely heard.

They used the same type of AR-15-style semiautomatic rifle Nikolas Cruz repeatedly blasted in the school shooting and in the same areas of the building where he struck.

Peterson was expected to be there Friday as an observer, without taking part. The city notified local residents they would hear gunfire continue as late as Friday evening and from more than a mile away.

Earlier Friday, nine members of Congress also spent an hour and 40 minutes touring the blood-stained and bullet-pocked halls of the deserted building, which still has broken glass and overturned tables from the 2018 Valentine’s Day slaughter. It is now scheduled to be demolished at a later date.

The House members — six Democrats and three Republicans on the House School Safety and Security Caucus — then had a roundtable meeting with parents and wives of some killed in the attack in the same hotel ballroom where the families had learned of their loved ones’ deaths.

Cruz, a former Marjory Stoneman Douglas student, was sentenced to life in prison after pleading guilty in 2021.

Peterson had been just feet from the door of the school building, with his gun drawn, when he instead moved away from the school and waited next to an adjacent building for 40 minutes.

He argued he did not hear the gunfire and could not tell where the gunshots were coming from — claiming he would have raced in to help had he known the shooter was inside.

“Those were my kids in there,” Peterson told NBC’s Today Show in 2018. “I never would have sat there and let my kids get slaughtered. Never.”

The Broward Sheriff’s Office was also named in the lawsuit, which was brought by victims’ families who accuse him of knowing Cruz was inside but being too fearful to perform his duty.

They are seeking unspecified damages.

The 60-year-old sheriff’s deputy was acquitted in June of criminal charges related to his alleged cowardice, including felony child neglect.

Tony Montalto, president of Stand with Parkland, a group that represents the families, said the re-enactment “is designed to disprove some of the statements that were made during the criminal trial.”

Montalto’s daughter, 14-year-old Gina, died in the shooting.

“He failed to properly react to the tragedy, he failed to enter the building and he failed to render aid.”

Circuit Judge Carol-Lisa Phillips, who is presiding over the still ongoing lawsuit litigation, has not yet ruled as to whether the recording of the re-enacted gunfire will be admissible at trial.

A trial date has not yet been set.

With Post wires.