An Arizona mother attempted to blame someone else for the death of her toddler son and infant daughter after their bodies were found “cold to the touch” in a vehicle, still strapped into their car seats, according to court documents filed Wednesday.

Brittany Velasquez, 20, said she found her 2-year-old son and 10-month-old daughter inside a car parked outside her home in Superior on Monday. She reported the children were not breathing and they had blood coming from their mouths.

"It is known that the kids spent several hours in the vehicle as there was condensation on the inside windows of the vehicle and the children were cold to the touch,” court documents stated.

The children were pronounced dead at the scene and Velasquez was charged with first-degree murder, according to authorities.

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While being questioned by investigators, Velasquez said she dropped the children off with someone who was supposed to care for them. She reportedly attempted to blame her children’s death on her grandparents, who denied knowing any arrangement about caring for the children, FOX10 Phoenix reported. She also told police she dropped the children off at a babysitter before heading to work.

“[The unidentified person] stated she had no idea what was happening and did not know what Brittany was talking about," the document stated, blocking out the identify of the person.

Vincent Velasquez, the woman’s brother, told FOX10 Phoenix: “What my grandparents could only do is let Brittany stay at their house. Really, that was all they could do for the kids."

Velasquez was the last person to see the children alive and had placed them in the vehicle around 9:30 a.m. Monday before heading to work, officials said. She allegedly returned to find their bodies nearly 14 hours later. The children were found wearing the same clothes they had been wearing that morning.

Autopsies are being conducted to determine the cause of death.

Police received past calls related to Velasquez. An unidentified relative told police in January that Velasquez left the toddler and infant with relatives days at a time. Two other reports were made to Arizona Department of Child Safety about the children.

Velasquez is being held on $2 million bond.

The Associated Press contributed to this report.