HILLSBORO, Ore. » An Oregon father whose 6-month-old daughter died after he left her inside his car at his workplace for six hours will not face criminal charges.

The Oregonian reports that a Washington County prosecutor in the Portland suburb of Hillsboro announced that decision Friday, calling the death a tragic accident.

According to court documents, 38-year-old Intel engineer Joshua Freier told police he had forgotten his daughter, Jillian, was still in the car when he drove to work last Oct. 16.

Although the car became hot, a medical examiner determined that the baby likely did not die from the heat. An autopsy was inconclusive, but the medical examiner said it’s possible that her ability to breathe could have been compromised because of her upright position in her car seat. He also estimated she died within the first hour.

Senior Deputy District Attorney Kevin Barton says the finding that the baby’s death couldn’t be linked to heat was key in the decision not to file charges.