CHRISTIANSBURG — All charges were dropped Monday against a Blacksburg woman whose son died of heat stroke two years ago after being left in a car all day.

Mary Nelson Parks, 46, was charged with involuntary manslaughter and felony child neglect after accidentally leaving her son, Juan Turner Parks, in the car while she went to work on Sept. 7, 2007.

Parks went to pick the nearly 2-year-old boy up from Rainbow Riders day care center in Blacksburg about 5 p.m. and was told she had never dropped him off. She found him unresponsive in her car.

“She literally in her mind dropped him off that day,” Parks’ attorney, Dave Rhodes, said after her hearing Monday in Montgomery County Circuit Court.

He said Juan and Parks’ other son, who is in elementary school, had been sick all week. Parks had stayed home from work to care for them, straying from their normal schedule. The accident happened on her first day back to work.

Normally, Rhodes said, Parks would have had both children in the car with her, but on that day only Juan was with her.

In a written statement, Rhodes said, “Mary Parks is a caring and devoted mother, who will forever mourn the loss of her precious child.”

At Monday’s hearing, special prosecutor Frank Slavin from the Wythe County Commonwealth’s Attorney’s office said that after investigating the case, he found that there wasn’t enough evidence to proceed with the charges.

Under state law, a “willful act or omission” in the care of a care of a child must be shown for a conviction of child neglect.

Through Rhodes, Parks declined to comment after the hearing but issued a written statement that said, in part: “Like us, many parents know not to leave a child in a car, but very few people know that they can unknowingly do this.”

The release included several tips “that can be taken to prevent such a tragedy.” One tip is to keep a stuffed animal in the car seat, then move it up front with the driver when the child is placed in the seat.

Since her son’s death, Parks has been involved in an organization called Kids and Cars. Its mission, according to its Web site, is “to assure no child dies or is injured in a non-traffic, motor vehicle related event.”

Her case had been scheduled for a three-day jury trial last December, but was postponed for a year.