By Dave Jordan, NEWS 9

OKLAHOMA CITY -- The drowning of a 2-year-old girl last week sparked questions on the possibility of dry drowning.

Two-year-old Allie Croom died last week at Lake Stanley Draper. Police have accused Donald Reeser of dunking the girl's head under water until she drowned, but Allie's mother said Reeser did not do it. She said Allie walked out of the water on her own and was later rushed to the hospital when she started coughing up water.

Investigators are now trying to determine whether Reeser killed the girl or if the drowning was an accident.

Doctors agree death by drowning can happen hours after a person is out of the water. Also known as delayed drowning or even parking lot drowning, this can occur when water is swallowed while swimming.

"Some of that waters gets down in the lungs and it's called Acute Respiratory Distress Syndrome (ARDS) where the lungs aren't working properly and that can cause a problem," said NEWS 9 medical expert Dr. Mary Ann Bauman.

Dry drowning accounts for about 15 percent of the nearly 4,000 people who drown each year. A case of a 10-year-old boy from South Carolina was reported last summer. Johnny Jackson died one hour after he went for a swim in a neighborhood pool. Relatives of the boy said they noticed no change in his behavior even though his lungs were filled with water.

The highly-publicized death led many instructors to inform swimmers about dry drowning.

"For the most part, parents are unaware of what delayed drowning is or what parking lot drowning is, so it's something that I teach to kids and parents I teach lessons to," said swimming instructor Chanel Henry.

Dr. Bauman said if a swimmer is extremely tired, has shortness of breath or any breathing problems that could be a sign that something is wrong and medical attention should be sought.