An autopsy performed on the Iowa parents and their two children who went to sleep inside of a Mexican condo and never woke up died by inhaling toxic gases, according to a press statement from Quintana Roo state attorney general's office.
Kevin Wayne Sharp, 41; his wife, Amy Marie Sharp, 38; Sterling Wayne Sharp, 12; and Adrianna Marie Sharp, 7, died as a result of "asphyxiation by inhalation of toxic gases," the statement read.
The findings are based on an autopsy that the AG said was performed between 36 and 48 hours inside the Tao condominium in the municipality of Tulum after authorities estimate the Sharps passed away.
Quintana Roo's state attorney stressed that the cause of death "ruled out violence or a suicide."
"During the inspection and expert analysis in the area, the bodies … did not show signs of violence, nor evidence to suggest disturbances inside the room, so that as a fact it is ruled out violence following [a] possible robbery," the state attorney said in the statement.
"To my knowledge, they went to sleep and never woke up," Amy Sharp's cousin Jana Weland told ABC News this week.
So far, neither the specific nature of the gaseous substance nor its source has been determined.
But the state attorney noted that experts and firefighters were conducting "a physical inspection of the gas installation of the room" to help render what exactly lkilled the family.
There will be more tests conducted and further details released in the next 10 days, according to the statement.
The family flew out of St. Louis and landed in Cancun, Mexico on March 15 to meet with friends to enjoy time at a water park.
The Sharps never made it to the waterpark, according to Weland, who said it was the second trip south of the border for the Sharp family.
When they didn't return stateside on Wednesday as scheduled, relatives in the family's hometown of Creston, Iowa became concerned and reported them missing.
Weland said that it was "unusual" that they weren't posting photos because "last year they shared pictures about every day."