A luxury hotel in Mexico owned by Hyatt has temporarily suspended normal operations following the deaths of a California couple, the hotel told CBS Los Angeles.

Abby Lutz, 28, and her boyfriend John Heathco, 41, were found dead in their hotel room last Tuesday. 

"Our top priority is the safety and wellbeing of guests and colleagues and the property will not resume normal operations until our investigation is complete," a Hyatt spokesperson wrote in a statement to CBS Los Angeles.

Prosecutors in Mexico's Baja California Sur state said last week that autopsies suggest Lutz and Heathco died of "intoxication by an undetermined substance." Local police initially said gas inhalation was suspected as the cause of death.

The state prosecutors' office said the bodies showed no signs of violence. The office did not say what further steps were being taken to determine the exact cause of death.

Authorities said the two had been dead for 11 or 12 hours when they were found in their room at Rancho Pescadero, a luxury hotel near the resort of Cabo San Lucas late Tuesday.

Lutz's family told CBS News that days before their deaths the couple was treated for what they thought was food poisoning. They spent the night in a Mexican hospital where they were treated for dehydration, her family said. 

The next day, they were back at their hotel.

"She said, it's the sickest she's ever been," said Lutz's stepsister, Gabby Slate, adding that Monday night was the last time the family heard from her.

"She texted her dad and said, 'good night, love you,' like she always does and that's the last we heard from her," said Lutz's stepmother Racquel Chiappini-Lutz.

Meanwhile, the sibling paramedics who responded to the incident are now saddled with medical bills after having fallen ill themselves, according to a fundraiser for the pair.

Fernando Valencia Sotelo and Grisel Valencia Sotelo, who tried to revive the couple, "were overcome" as they attended to the couple.  Now the two are receiving medical care at a private hospital, a fundraiser for the siblings states.

In:
• Mexico
• Carbon Monoxide