A baby was found dead in a parked car Wednesday evening outside a Procter & Gamble plant near Cincinnati, after her mother left her there while she was at work, police say.

The 15-month-old girl was found in the P&G employee lot at the Mason, Ohio, plant around 5 p.m.

Doyle Burke, chief investigator for the Warren County Coroner's Office, said the mother appeared to have left the child strapped in a car seat all day while at work, then called 9-1-1 when she returned to the vehicle and found the child unresponsive.

Although no official cause of death was announced, Burke said investigators believe high temperatures inside the car were a factor.

“Even though it wasn’t sweltering hot today, it’s obviously going to be hotter in the car,” Burke said. “And certainly a 15-month-old is more susceptible to something like this than an adult.”

An official autopsy was set for Thursday.

No charges were filed against the mother, who is an employee at P&G.

The company released a statement Wednesday night expressing their condolences.

“Our thoughts and prayers are with the affected family. We are providing our full support to both the family and local officials.”

The Associated Press contributed to this report.