The King County Prosecutor’s Office filed charges of manslaughter in the second-degree June 27 against Alberto Rios in the death of his 7-month-old son.

This charge is filed when a death is the result of negligent behavior, said Dan Donohoe, King County Prosecutor’s Office spokesman.

The infant died from burns and smoke inhalation after he fell into a fire pit in the family’s backyard. Rios had been drinking and had fallen asleep with the infant on his chest, reports said. He woke up to discover the baby deceased.

Rios is now being held on $1 million bail at the Norm Maleng Regional Justice Center in Kent. An arraignment date is scheduled for July 9.

If convicted of the charge, Rios faces 21 to 27 months in prison, Donohoe said.

The infant was found deceased in a backyard fire pit June 22 in the 2600 block of Southwest 333rd Place.

The King County Medical Examiner’s Office conducted an autopsy Tuesday that revealed the infant had ingested soot from the fire into his esophagus. This indicates the child was alive at the time he entered the fire pit, according to police documents.

Rios told authorities that he and the child’s mother threw a party Saturday night, June 21. He said he consumed between three and six alcoholic beverages, then later fell asleep on a bench by the fire with his infant son on his chest and his 4-year-old daughter at his side, according to police documents.

Rios awoke later and could not find either of his children. He then entered the home looking for them and woke his wife to ask her where they were, according to the documents. Next, he ran outside looking for the baby, which he found covered in burns and ashes in the fire pit.

He removed the deceased infant from the pit and cradled the baby, rocking back and forth while crying until fire and rescue arrived, according to police documents. South King Fire and Rescue and Federal Way police responded to the home at 12:02 a.m. Sunday. When rescuers arrived on scene, they found the boy’s body suffered several burns and a head injury.

It remains unclear to investigators how the infant moved from the bench to the fire pit. The fire pit did not have a safety structure surrounding it and was described by police spokeswoman Cathy Schrock as a “hole in the ground.” Schrock was also unsure whether the infant had been seated in a carrying device or directly on the bench.

Infants ages 7-9 months old are generally able to move about on their own in a limited manner. They may be able to scoot, rock or crawl, and some can sit or pull themselves to a standing position on their own, according to a Mayo Clinic article titled “Infant development: What happens from 7 to 9 months?”

Statements from both parents and witnesses were taken by police Sunday before all were released from custody the same day. A search warrant was issued to investigate the home and a blood sample was taken from the father at that time, Schrock said.

The Department of Social and Health Services has no record of reported abuse or neglect to either of the couple’s children, communications director Thomas Shapley said. The agency is working with the mother on a family safety plan, he said.

“We will come into a case like this and try to develop a family safety plan of one sort or another,” Shapley said. “That could cover a broad range of things.”

The plan will be more fully developed once autopsy results have been reviewed by the agency, he said.

Contact Jacinda Howard: jhoward@fedwaymirror.com or (253) 925-5565.