FORT LAUDERDALE, Fla. — When Coral Springs police officer Gil Monzon arrived at Marjory Stoneman Douglas High School minutes after a gunman unleashed a massacre that killed 17, he says he found two Broward County sheriff’s deputies in the parking lot.

He asked for the gunman’s location, and was told they didn’t know, but he could see a body next to the freshman building and bullet marks in its third-floor windows.

He said in reports released Monday that he and three other Coral Springs officers immediately went to the building, checked the body and then entered, where they immediately found a victim standing against a wall and then falling to the floor.

The four pages written by three officers detail what they found when they arrived at the Feb. 14 shooting that also left 17 wounded. They corroborate earlier reports that the first Broward deputies at the scene failed to enter the building to confront the gunman and assist the wounded.

Officer Tim Burton, the first on-duty Coral Springs officer to arrive, grabbed his rifle and was directed toward the freshman building, where he found Deputy Scot Peterson, the school’s security officer, taking cover behind a concrete column.

He said Peterson told him he had not heard any shots for several minutes, but to watch his back, that the gunman might be in the parking lot.

Peterson would soon retire from his deputy job under criticism from Sheriff Scott Israel, who said he should have immediately entered the building to find the killer. Parents, meanwhile, speculated that victims on the third floor could have survived had first responders reached them more quickly. Ryan Petty, whose daughter Alaina died in the attack, tweeted over the weekend: “6 on the 3rd may have lived if anyone had gone in.”

Monzon said that after dragging the victim who collapsed out of the building, he and three other officers went back inside.

“The hallway was quiet and full of thick smoke from gunfire,” he wrote. They found a female hiding in an office and led her outside.

By then, another team of Coral Springs officers entered the building from the other side, so to avoid accidentally firing at each other, Monzon and his team moved to the second floor, where they found students and teachers hiding in classrooms. Still unsure if the gunman was in the building, they left survivors locked in classrooms and moved to the third floor, where Monzon said he “encountered several deceased students throughout the hall.” He was then sent to help clear a nearby building.

Police say Nikolas Cruz, 19, a former Stoneman Douglas student, committed the mass shooting and then fled the building after his gun jammed. They say he was captured an hour later about a mile away.