PEORIA, Ill. (WMBD) — Nigel Ragon’s family now knows what killed him after 15 years.

The update comes after officials reopened and reviewed the 2007 death investigation of Ragon in April. A multi-agency team determined that the infant died of asphyxiation, but they are unsure of how it happened.

The re-investigation includes Peoria County Coroner Jamie Harwood, Woodford County officials, and the Illinois State Police.

The determination that Ragon died from asphyxiation was made using a combination of autopsy, toxicology, and police reports, as well as previous interviews with the mother and father.

Harwood said two of the main reasons officials decided to revisit this case were — one — the manner in which Ragon died and two — the circumstances surrounding his mother, Stephanie Jones, 35.

The case resurfaced after his half-brother, 8-year-old Navin Jones, was killed, and their mother, Stephanie, was arrested in connection.

Harwood said the team is in contact with the baby’s father, who Harwood said is eager to have closure on his son’s death.

The next step is to do a doll reenactment, which the father agreed to help authorities with. Harwood said it will be “exceptionally pivotal” to learn how Nigel died.

The reenactment would help answer questions like how the infant was placed to sleep, and how the baby was found when his father returned home.

Harwood said Ragon’s body will not be exhumed and there’s been no signs of physical trauma. A manner of death is expected to be known in seven to 10 days.

That reenactment is expected to take place this week.