A 4-month-old boy died at the hospital Monday evening after he was found unresponsive in his father's car at BART's El Cerrito Plaza station, a BART spokesman said.
The Contra Costa County Coroner's Office on Tuesday identified the baby as Everett Carey.
It appears as though the child had been in the car most of the day, Johnson said.
He said investigators have learned Everett's father typically leaves him with a babysitter or some type of day care in the morning and then goes to the station to take a train.
When Everett's mother discovered her child wasn't where he was supposed to be, she went to the station and found the boy in a car seat in the car.
Everett was taken to Doctors Medical Center in San Pablo by El Cerrito fire personnel and his parents followed in a separate ambulance, according to Johnson. The baby boy was pronounced dead at 6:02 p.m., Johnson said.
With a temperature of 67 degrees in El Cerrito Monday, the inside air temperature of the car would likely have been in excess of 115 degrees, according to Jan Null, adjunct professor of meteorology at San Francisco State University.
The baby's death is the sixth of its type in the country this year and the first in California, for the year. Since 1998 at least 421 infants and children have died in hot vehicles in the U.S., with 35 of those incidents happening in California, Null said.
"Clearly what happened today ended up being a tragedy for everyone involved," Johnson said.