The Baja California Sur Attorney General’s Office identified the couple as John Heathco and Abby Lutz. Lutz was from Newport Beach, according to the office, but officials did not say where Heathco was from.
The pair was staying at the Hyatt’s luxury Rancho Pescadero resort and in the days before their deaths went to the hospital because they thought they had food poisoning, according to a GoFundMe page shared by Lutz's family.
Officials said their suspected cause of death was inhalation of gas.
"While on a beautiful trip to Mexico, Abby and her boyfriend thought they had food poisoning and went to the hospital to get treatment."
"We were told they were feeling much better a few days later," the family wrote on GoFundMe.
"We received a phone call saying that they had passed away peacefully in their hotel room in their sleep. We have been told it was due to improper venting of the resort and could be carbon monoxide poisoning."
Lutz's family said her death was "completely unexpected," and that her dad had been looking forward to seeing her for Father's Day weekend.
In a statement, Lutz's family thanked the public for the ongoing support.
"This Father’s Day has special significance to the Lutz family as Abby had planned to spend the day with her father, Tony. The family now spends the day mourning her loss and reflecting on all the wonderful memories we have of her.The support the family has received over the past few days has been beautiful and compassionate. We are forever grateful to those who have provided assistance to help us bring Abby home and lay her to rest. There have been many, and they hold a special place in our hearts.As we try to piece together Abby’s final hours, we are monitoring information as it emerges. We appreciate those in Mexico who have come forward with information, some at great personal risk. These people are heroes. We urge others with information to make their voices heard in some way," the statement read.
According to Heathco's LinkedIn page, he is the founder of Newport Beach-based LES Labs, a nutritional supplement manufacturer. Lutz's Facebook page states that she lived in Ladera Ranch and was working as a nanny.
Authorities said there were no signs of violence on either of the couple’s bodies when first responders found them around 9 p.m. Tuesday in their hotel room.
The couple had been dead for about 10 to 11 hours before their bodies were discovered by police and paramedics. Police said they were responding to a report of two Americans who were unconscious in their room.
The Hotel Rancho Pescadero, a luxury Hyatt hotel, is in the seaside community of El Pescadero, which is located between Todos Santos and the resort of Los Cabos.
There have been several cases of such deaths in Mexico due to poisoning by carbon monoxide or other gases. Such gases are often produced by improperly vented or leaky water heaters and stoves.
In October, three U.S. citizens found dead at a rented apartment in Mexico, apparently victims of gas inhalation.
In 2018, a gas leak in a water heater caused the deaths of an American couple and their two children in the resort town of Tulum, south of Playa del Carmen.
An inspection revealed that the water heater at the rented condominium was leaking gas. Prosecutors said the gas leak was perhaps caused by a lack of maintenance or the age of the equipment.
In 2010, the explosion of an improperly installed gas line at a hotel in Playa del Carmen killed five Canadian tourists and two Mexicans.
In that case, prosecutors said the gas line, apparently meant to fuel a pool heating unit, was not properly installed or maintained. They said gas leaking from the line may have been ignited in an explosion by a spark from an electric switch or plug.
In a separate case in the Caribbean coast resort of Playa del Carmen, prosecutors announced Wednesday that a judge ordered three men to stand trial on homicide charges in the May 30 killing of an Italian woman at a restaurant.
The woman was a longtime resident of Playa del Carmen, and was not a tourist. Prosecutors did not provide information on a possible motive in that case.
The Associated Press contributed to this report.