A four-month-old girl died after being left in a vehicle by her father, police say.
It is not known why the 56-year-old man, understood to be the child's adoptive or foster father, left the tot in the vehicle as he returned to work.
But shocked passersby called emergency services after noticing the distressed baby.
Paramedics in Phoenix, Arizona, tried to resuscitate her but she was pronounced dead at the scene on Tuesday.
Speaking at press conference, captain Rob McDade, of the Phoenix Fire Department, said: "The child was probably deceased for an unknown amount of time and enough to where we just could not intervene.
"When he decides to leave work, after 3:30 or so, is when he noticed that he forgot his child in the car.
"Him and his wife are people that are always willing to help others. This is a mishap that happened."
There is no indication of foul play at this stage.
It is said the man works in administration at Washington Elementary School District.
Police say the man and his wife are parents of adoptive and foster children, according to abc15 .
"Our hearts go out to our staff member, his family and all of his colleagues who are grieving this tragic loss," the school district said.
The mercury was forecast to hit 32.2C in the area on Tuesday.
It's unclear what the temperature in the van was.
Enquiries continue.
