An 18-month-old Arkansas boy died inside a dishwasher that began running when its door closed, police have confirmed.

Authorities are still investigating, but said the boy's death Wednesday afternoon appeared to be accidental. No signs of prior injury were found, and the cause of death likely was heat exposure.

The boy's 13-year-old brother found him inside the appliance, and he died before paramedics arrived at the home in the town of Romance, north of Little Rock.

"The baby's blanket was lying in front of the dishwasher, so [the brother] opened it," said Jeremy Clark, chief deputy in the White County Sheriff's Office.

"What we have found out so far would suggest that this is a tragic accident, however, the case is still open and we're still looking," Clark said.

The dishwasher, which was empty when the child got inside, was a Maytag model that automatically started running when the door closed, police said.

"The death of any child is tragic," said Monica Teague, a spokeswoman for Whirlpool Corp., which makes Maytag dishwashers.

She said Whirlpool's appliances are certified for child safety through an independent product testing corporation.

"All our appliances go through rigorous testing," Teague said.