Gunfire to ring out at Parkland school once again. A reenactment is planned Friday.

PARKLAND, Florida — Someone carrying an assault-style rifle will walk through the halls of Marjory Stoneman Douglas High School on Friday and reenact the deadliest high school shooting in U.S. history.

They'll retrace the Parkland shooter's steps and move floor by floor through the three-story building, firing live ammunition through shattered classroom windows and into hallway alcoves where students lay trapped and wounded five years earlier.

The reenactment is part of a civil lawsuit against former Broward County school resource officer Scot Peterson, who did not enter the building or engage the teenage gunman at any point during the shooting.

“Be advised we have possible, could be firecrackers," Peterson said into his radio as he waited outside. "I think we have shots fired, possible shots fired, 1200 building."

A jury acquitted Peterson in June of all criminal charges stemming from his failure to rush into the 1200 building during the killer's six-minute rampage on Feb. 14, 2018, but debate over his inaction is still playing out in civil court.

Peterson said he stayed outside because he couldn't tell where the gunshots were coming from. Attorneys representing the families of Stoneman Douglas students Meadow Pollack, Luke Hoyer, Alaina Petty, Alex Schachter and survivor Madeleine Wilford say the reenactment will prove that he could, and did.

'Done wrong,' reenactments can harm a case, professor says

Broward County Circuit Judge Carol-Lisa Phillips signed off on the reenactment in July. The lawyers initially planned to use blank rounds to recreate the shooting but decided that live ones, fired into a ballistic bullet trap, will make for a more accurate recreation.

"Done right, reenactments can be a very powerful tool for the presenting side," said Bob Jarvis, a law professor at Nova Southeastern University in Fort Lauderdale. "But done wrong, they can really sink the presenting side’s case."

Jarvis said the key is to have the reenactment stick closely to facts that the presenting side can prove in court. The more liberties and guesses they take with the reenactment, the more likely the jury will see through the attempt and discredit all of the presenting side’s evidence and testimony — even if the rest of its case is strong.

Phillips has yet to rule on whether any recordings of the reenactment would be admissible at trial. She said Peterson's team of lawyers and defense experts could conduct their own reenactment, but both parties agreed to just one.

"We did not see the need to put the community through that twice," Peterson's attorney Michael Piper told the judge at a hearing in July.

Building untouched since shooting, soon to be demolished

The judge ordered the plaintiffs' and defendant's legal teams to cover all expenses for the reenactment, including payment for the school personnel who will stand guard to trigger the fire alarm at the precise point it occurred within the shooting spree.

The Broward County school board issued a communitywide notice about the plan, "which is a court order and is not organized or controlled by Broward County Public Schools," it said. No members of the media or public will be allowed on campus during the reenactment.

The freshman building at Stoneman Douglas has been preserved as an active crime scene since the day of the shooting. Reporters who toured it during the gunman's sentencing trial last year said it was like walking into a graveyard. The walls and floors are still stained with blood.

Max Schachter, whose 14-year-old son Alex was one of the first students killed, challenged congressional leaders to walk beside him through the building Friday before it’s torn down. The building is slated to be demolished before students return for classes Aug. 14.

South Florida lawmakers Jared Moskowitz, who grew up in Parkland, and Mario Diaz-Balart, both members of the Congressional Bipartisan School Safety and Security Caucus, have promised to be there.

Hannah Phillips is a journalist covering public safety and criminal justice at The Palm Beach Post, part of the USA TODAY Network. You can reach her at [email protected].

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