HOUSTON -- Two young boys died in Harris County in separate incidents less than 24 hours apart after adults seemingly forgot they were in the back seat, KPRC Local 2 reported Friday.

Cameron Boone, 3, died Thursday after he was left in a pickup truck in the parking lot of North Cypress Medical Center. Another 3-year-old boy died Wednesday after a relative left him strapped in a car seat in a parking lot in Webster.

Investigators said each child's death appeared to be accidental. In both instances, the adult allegedly forgot to drop the child off at day care.

Neither adult has been charged. Harris County District Attorney Ken Magidson said every case is different.

"One of the factors that we look at is the person's state of mind -- that is, was it acted on intentionally, recklessly, negligently or omission?" he said. "All of those have separate indicators if liability was involved."

Child Protective Services officials said there are ways for drivers to prevent themselves from unintentionally leaving a child in a car.

"If you're transporting your child, put something else in the back," spokeswoman Gwen Carter said. "Your lunch, another set of keys, your purse, your briefcase … so you remember to go to the back of your car."

Houston Fire Department officials said it does not take long for a child to fall victim to the heat.

"It's just an overheating process," Executive Assistant Chief Rick Flanagan said. "The body can't cool itself any more. The person and everything just starts to shut down."

Doctors said children react to heat faster than adults because the regions of the brain that control body temperature are not fully developed.

In addition to keeping a purse or briefcase in the back seat, an organization called Kids and Cars recommended keeping a large teddy bear in the child seat when it's not in use. When the child is in the seat, put the stuffed animal in the front as a reminder the child is in the back.

Experts said parents should warn children not to play in or around vehicles. Parents were reminded to keep the doors and trunk locked and to keep the keys out of reach to prevent children from getting into a dangerous place.