LITTLE ROCK, Ark. (AP) -- An Arkansas 911 operator did not enter a call into a computer system that would have notified police and fire dispatchers of a mother and son trapped inside a vehicle in a pond, authorities said Wednesday.

The woman died hours later, and her 5-year-old son was in critical condition Wednesday, police said.

The Little Rock operator who handled the call from 39-year-old Jinglei Yi has been placed on paid administrative leave while authorities try to figure out what happened. The operator has not been charged with any wrongdoing.

Yi called 911 about 8 a.m. Monday after her vehicle hit a patch of ice, went over a curb and ended up in the pond, Police Department spokeswoman Sgt. Cassandra Davis said.

A county dispatcher transferred the call to the 911 operator, who spoke with Yi briefly before hanging up and contacting an ambulance service.

An ambulance was dispatched a few minutes later to the west Little Rock pond, but police officers and firefighters weren't dispatched until about a half-hour later — after the ambulance service called to verify that they were en route.

When the ambulance got there, the employee realized something was wrong because there were no police cars at the scene, Fox16.com reported. That's when they radioed back to dispatch to find out what was happening.

"Right now, we don't know where the breakdown occurred. If is was an operator error or if it was a mechanical error," says Little Rock Police Sgt. Cassandra Davis.

Laura Martin, who directs the city police and fire departments' communications branch, said the operator did not enter Yi's call into a computerized dispatching system that would have alerted police and fire dispatchers.

The operator also ended Yi's call instead of using a transfer option that would have allowed her to keep Yi on the line while contacting the ambulance service, she said.

"Proper protocol would be ... we have a one-button transfer switch where you get (the ambulance service) on the line and you remain on the line with them until you're sure that they have handled the call," Martin said.

On the 911 call, which The Associated Press obtained under the Freedom of Information Act, a county dispatcher describes Yi's situation to the operator in Little Rock while Yi remains on the line.

Then, Yi describes her location and says there is water in her vehicle.

"The water is in my car right now," she said.

The Little Rock operator asked Yi for her name and asked her to hang on.

"OK, ma'am, we're going to get some help on the way for you, OK?" the operator said.

"OK. Thank you," Yi said. Then the call appears to end.

Neither Davis nor Martin would identify the operator, who was hired in March and completed a six-month probation period in September.