(Renton, WA) -- New details are coming to light regarding the deaths of two teenage sisters and their father inside their apartment. The family members were found dead December 11th in their with no visible injuries or trauma to their bodies. Police say there was also no sign of carbon monoxide in the apartment. The King County Medical Examiner's office then performed autopsies on the three and did not uncover any "obvious manner of death"--noting that further testing was necessary.

Well, now they're another layer of mystery. Investigators say It appears 17-year-old Adriana Gil and 16-year-old Mariel Gil died on December 5th--five days before their 33-year-old father Manuel Gil died. Adding that environmental factors including the warmth of the apartment's interior could have affected that timeline.

The investigation remains ongoing.

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