For the second time in less than a week, a small child has died inside a vehicle parked in the Inland area's harsh summer heat.

Authorities will conduct an autopsy to determine if the second death was caused by elevated heat inside the vehicle, parked in desert temperatures that reached 115 degrees.

Sunday, 22-month-old Mia Parham of Desert Hot Springs was found dead after apparently being inside a vehicle for more than three hours following a family miscommunication, authorities said.

Mia's parents, Anthony Parham, 32, and Katrina Parham, 26, were devastated by Mia's death.

"We're just overwhelmed," Anthony Parham said Monday. Katrina Parham was too upset to talk.

A Riverside County coroner's report said Katrina Parham was preparing about 1:30 p.m. to take her nieces back home after an overnight stay and Mia apparently got into one of two vehicles parked in the driveway. But the mother asked another daughter to put the nieces in the second vehicle.

Katrina Parham returned home about 3:15 p.m. At about 4:45 p.m., a daughter went to look for some nail polish in one of the vehicles and discovered Mia, unresponsive, the coroner's report said. The parents called 911 but paramedics could not resuscitate the toddler.

On Friday, 3-year-old Maryah Ponce succumbed to the sweltering heat in Rialto after foster mother Linda Montano forgot to take the girl out of a sport utility vehicle for 20 minutes, authorities said.

As in Maryah's death, authorities in Mia's case said they would await autopsy results before deciding about possible prosecution.

Maryah's autopsy was conducted Monday but the San Bernardino County coroner's office said further test results, which could take months, were needed before a definite cause could be attributed.

Mia's autopsy had not been scheduled as of Monday afternoon, Riverside County sheriff's Sgt. Mark Lohman said

"We don't know yet if this resulted from the heat or a previous medical condition," Desert Hot Springs Police Chief Paul Stotesbury said.

Grieving family members gathered Monday at the Parhams' home on Tamar Drive. Mia's step-grandfather, Deno A. Lightfoot, 31, of Banning, said her death was an accident.

"This is a nightmare that no one could imagine," Lightfoot said. "It's important to know there was no negligence in this. As far as I'm concerned, what happened was pure accident."

Nevertheless, Lightfoot suggested that other parents could learn from Mia's death.

"If there's a lesson to be learned in all this, it's you gotta keep up with your kids," Lightfoot said. "Because no matter how young, they're smart enough to get away from you. It's just a tragic, tragic accident that nobody wanted or expected."

Mia was precious to all her relatives, Lightfoot said.

"She is a missing piece of everyone's heart, in this house and my house," Lightfoot said, weeping softly.

Mia was the youngest of six children, Lightfoot said.

Meanwhile, the biological family of Maryah Ponce continued to struggle with questions over their daughter's death.

Maryah was placed with a Rialto foster family registered through Canyon Acres, a state-licensed foster agency, said Michael Riley, director of children and family services in Orange County.

Maryah's two other siblings were also being cared for in the same home, and have been removed and are now staying at Orangewood Children's Home in Orange County, Riley said.

Riley said he couldn't comment directly on the case while investigations into Maryah's death were pending.

Last summer, two children died within less than a week of each other after being left inside vehicles in the summer's heat.

On Aug. 19, Steve Ray Thomas of Needles forgot to take his infant son, Kevin, out of his car following a trip to the Colorado River. He was not charged in the death. Temperatures outside Thomas' car were estimated at 115 degrees.

Four days earlier, 6-month-old Kaitlyn Russell of Corona was left alone in a van for several hours by her baby sitter. Outside temperatures reached 100 degrees, causing the baby to die of hyperthermia in less than half an hour, authorities said. Temperatures inside the vehicle reached an estimated 130 degrees.

The baby sitter, Suzie Calderon of Corona, was ordered to stand trial on manslaughter and child abuse charges during an April preliminary hearing in Riverside County Superior Court.

Kaitlyn's mother, Tammy Russell, has since devoted much of her life to spreading the word about the dangers of leaving small children in cars. She says education is the key.

"I don't think people are aware how quick temperatures in the interior of a car can rise, even if the windows are cracked," said Russell, who added that criminal charges are rarely filed in cases where the victim's parents are at fault.

San Bernardino County Supervising Deputy District Attorney Vic Stull said that's likely because prosecutors feel the parents have suffered enough.

"They balance punishment with the degree they (the parent) have already been punished by the death of their child."