Scot Peterson, left, sits in court Tuesday with his attorney.
CNN  — 

Jurors concluded a third day of deliberations on Wednesday without reaching a verdict in the trial of the former school resource officer who stayed outside during the 2018 massacre at a Parkland, Florida, high school in a rare trial focused on law enforcement response to a mass shooting.

Deliberations are expected to resume Wednesday morning.

State prosecutors accuse Scot Peterson, 60, of ignoring his training and doing nothing as 17 people, including 14 students, were gunned down at Marjory Stoneman Douglas High School – the deadliest high school shooting in US history. His attorney argued the then-deputy for the Broward Sheriff’s Office didn’t enter the building because he couldn’t tell where the shots were coming from.

“His job was to go and investigate and make his presence known, and that simply did not happen,” Assistant State Attorney Christopher Killoran said in closing rebuttal arguments Monday.

The verdict is anticipated as America’s scourge of mass and school shootings drags on, with about 200 attacks on K-12 campuses since the Valentine’s Day massacre at the Parkland school. Some 331 shootings with at least four wounded, not including a shooter, have been recorded so far this year, Gun Violence Archive reports.

After about 3 1/2 hours of deliberating, jurors asked Tuesday morning to view “poster-sized evidence” and other visual aids used by the state and defense during their presentations. The court declined to provide the visual aids since they were not introduced into evidence, and state Judge Martin Fein told jurors they had all the evidence introduced by both sides.

Jurors asked another question Tuesday afternoon regarding a password needed to access a hard drive so they could review a piece of the state’s evidence. Prosecutors provided jurors with instructions and the password.

Peterson is accused of failing to confront the gunman according to his active shooter training, instead taking cover for more than 45 minutes outside the school’s three-story 1200 building before the gunman was apprehended.

Peterson “left behind an unrestricted killer to spend the next 4 minutes and 15 seconds wandering the halls at his leisure,” Assistant State Attorney Kristen Gomes said. “Because when Scot Peterson ran, he left children trapped inside of the building with a predator unchecked.”

Peterson has pleaded not guilty to eleven counts, including seven felony counts of child neglect and three misdemeanor counts of culpable negligence for his alleged inaction to stop the shooter. He also faces one misdemeanor count of perjury for lying to investigators about the number of gunshots he heard after arriving at the scene of the shooting, according to prosecutors.

The charges against Peterson reflect the deaths and injuries of eight students – seven of them minors – and two school employees on the third floor of the 1200 building: Teacher Scott Beigel and students Cara Loughran, Meadow Pollack, Joaquin Oliver, Jaime Guttenberg and Peter Wang all were killed, while teacher Stacey Lippel and students Kyle Laman, Marian Kabachenko and Anthony Borges were wounded and survived.

Peterson, who retired as criticism of his alleged failure grew, never knew where the shooter was, defense attorney Mark Eiglarsh told jurors, pointing to other witnesses who testified they could not narrow down where the deadly shots originated.

“Two dozen witnesses came in here one by one and told you they couldn’t tell from the sounds precisely what area we’re talking about,” Eiglarsh said in his closing argument Monday.

And even if Peterson had known where the shooter was, speculation he could have made a difference is false, Eiglarsh argued.

The state’s “entire case hinges upon this erroneous belief that he knew that there were kids in that 1200 building being shot by this monster,” Eiglarsh said, asking jurors for a verdict of not guilty. “And that wasn’t proven because it didn’t happen.”

Only one person was responsible for the shooting, Eiglarsh argued: The shooter, who pleaded guilty to 17 counts of murder and 17 counts of attempted murder and was sentenced to life in prison without parole.

Trial focuses on law enforcement’s role

Peterson’s trial included testimony from former students, staff and members of law enforcement who supported the ex-deputy’s claim it was difficult to hear where the gunfire was coming from. Jurors also heard from witnesses who testified they knew the shots were emanating from the 1200 building, as well as law enforcement officers who testified their training dictated they move toward the sound of gunfire to confront a possible shooter.

Eiglarsh has emphasized Peterson was at the scene for the last 4 minutes and 15 seconds of the shooting, which lasted about 6 1/2 minutes. Peterson also arrived at the scene without a bulletproof vest or rifle and called for measures to lock down the school, the attorney told jurors.

But Peterson “left behind an unrestricted killer to spend the next four minutes and 15 seconds wandering the halls at his leisure,” Gomes said. “Because when Scot Peterson ran, he left children trapped inside of the building with a predator unchecked.”

Eiglarsh has emphasized Peterson was at the scene for the last 4 minutes and 15 seconds of the shooting, which lasted about 6 1/2 minutes. Peterson also arrived at the scene without a bulletproof vest or rifle and called for measures to lock down the school, the attorney told jurors.

“To sit in the calmness of a courtroom that is chill and mellow and try to go back and Monday morning quarterback is unfair and unjust,” he said.

Correction: A previous version of this story incorrectly identified one shooting victim. Eight students and two school employees were killed on the third floor of the 1200 building.

CNN’s Nouran Salahieh contributed to this report.