HOUSTON -- A 3-year-old boy died after being left in a hot truck at a northwest Harris County hospital. He was found in the parking lot of the North Cypress Medical Center on Highway 290 at about 3:30 p.m.

Cameron Thomas Boone was found lying on the front seat when his mother returned to the vehicle after working her shift, which started at 6:30 a.m. There was a key in the ignition and investigators believe the boy might have tried to turn on the vehicle before he passed out from the heat.

“The boy had gotten out of the car seat trying to get out of the car,” said Harris County Sheriff’s Office spokesman Lt. John Denholm. “We saw the key in the ignition. (He) was trying to put the window down or open the door and was unable to.”

Denholm said temperatures in the car could have reached as high as 150 degrees.

With the key in the ignition, the mother’s key remote would not work. It was then she saw her son’s lifeless body on the front seat of the car.

She flagged down security, which busted out the window. Emergency room doctors in the Cypress hospital tried to revive the boy, but it was too late.

Denholm said the mother is a hospital employee who drove to work and forgot her son was in the car. She was supposed to drop him off at day care, but told investigators she simply forgot about him.

“I never expected it to happen to one of the hospital employees,” said shocked eyewitness Adriana Sanchez. “They’re in the whole first aid area. So, you would never expect that.”

This is the second time in as many days that a small child has died in a scorching car.

The cases are eerily similar.

A 3-year-old boy died Wednesday after his grandmother left him in the car for 10 hours. That woman told police she also forgot to drop the child off at day care before she went to work.

That case has been referred to a grand jury without charges.