AUTOPSY results have indicated how an American couple and their two children died while on holiday at a Mexican resort.

The family who were reported missing by concerned family members when they didn’t return home from the trip, died from inhaling toxic gas at a rented condo on Mexico’s Caribbean coast, but there was no sign of foul play or suicide, authorities say.

The prosecutors’ office in the Caribbean coast state of Quintana Roo said on Saturday that “the cause of death was asphyxiation from inhaling toxic gases”. It said the type of gas hadn’t yet been determined but added that “any violent act or suicide has been discounted”.

Photos released by the office showed investigators in anti-contamination suits and firefighters with air tanks examining gas connections to a stove in the condo in Tulum.

The office said investigators “carried out a physical investigation of the gas connections in the room” and the civil defence office of Tulum would issue a technical report on the findings.

US officials identified the family as Kevin Sharp, 41, his wife, Amy Sharp, 38, and their children Sterling, 12, and Adrianna, 7. They were from Creston, Iowa.

The family was reported missing by relatives in their home town about a week after the family left for their holiday.

Creston police contacted the US State Department, and the bodies were found during a welfare check at the condo in Tulum, on the Yucatán Peninsula.

The Quintana Roo prosecutors’ office said the family had been dead for between 36 and 48 hours by the time they were found on Friday at the Tao condominium complex.

The Creston News Advertiser newspaper in Iowa reported that the family flew to Cancun on March 14. According to her sister, Amy Sharp texted their mother the next day to say they had reached Tulum, but relatives didn’t hear any more from the family.