Frantic calls released from Parkland shooting: 'I love you, it's going to be fine ... I need you to play dead,' mom says

Seventeen students and adults were fatally shot in the Feb. 14 school massacre.

"I love you, it’s going to be fine," a panic-stricken mother said over the phone to her child hiding in a classroom during the Parkland, Florida, school massacre. "Can you play dead? I need you to play dead."

The suspected school shooter, Nikolas Cruz, a former student, was arrested after the shooting. On Wednesday a grand jury indicted Cruz, charging him with 17 counts of premeditated murder in the first-degree and 17 counts of attempted murder in the first-degree.

School officer Scot Peterson, who was criticized in the wake of the shooting for not going into the school, can be heard telling a dispatcher, "We don't have any description but it appears to be -- shot -- shots fired" as gunfire is heard in the background. A minute later he shouts, "Get the school on lockdown, gentlemen!"

Peterson is heard warning officers not to enter "12 or 1300 building" and six minutes after making the initial call gives a description of the suspect, saying, "10-4 all units be advised a male in a hoodie possible AR-15 or AK-47."

One man who was not at the school but was on the phone with a student inside told the 911 operator that two students were alone huddled in one classroom.

That man acted as the liaison between the hiding student and the dispatcher.

"Don’t talk, just be quiet," the man tells the student.

"Try hiding behind the curtain or something," he says, later asking if there's a cabinet or a closet in the room.

The operators asks if there are teachers there and the man says just two students.

"She’s hearing yelling in the hallway," the man said.

"Tell her to be quiet," the operator said. "We don’t know -- there’s a lot going on, just tell her to be quiet."

"Let her know she’s doing good, just keep try to keep her calm," the operator adds. "She’s doing good. All police, we got extra units from other places in other cities coming."

The man relays to the student, "Be calm, be quiet, help is on the way. Police from all over are coming."

"There’s no place to hide," the man tells the dispatcher. "They are crouched."

Next to the man was the student's mother, listening on speaker phone.

Later the man says, "Somebody just entered the room."

"OK, who is it that entered the room?!" the operator asks.

The man asks into the phone, "Is it the police?!"

Then the mother listening over the phone says, "I love you! I love you! It’s mom."

The man tells the dispatcher, "It’s the police, they said put your hands up."

"I love you, I love you, it’s going to be fine," the mother says. "Can you hide from there? Can you play dead? Can you play dead? I need you to play dead."

Finally the man says the student told him the police arrived.

"The police are there right now and they are checking the injured out," he tells the dispatcher. "The police are escorting the students out of the classroom."

"OK alright, sir," the operator says. "Thank you so very much, sir."

"Thank you for all your help," he replies. "I hope this turns out to be not as bad."

"Yes, I hope so too," the operator adds.

ABC News' Malka Abramoff, Katherine Carroll, Alexandra Faul, Rachel Katz and Brendan Rand contributed to this report.