MEXICO CITY (AP) — A prosecutor in Mexico says a gas leak in a water heater is suspected in the death of a southwest Iowa couple and their two children last week. The head prosecutor of the Caribbean coast state of Quintana Roo told local media today (Monday) that the water heater “was leaking gas, maybe from use or lack of maintenance.” Miguel Angel Pech told the Radio Formula station that “a high level” of gas was found in the rented condo where the couple was staying.

Autopsies indicate the family died from inhaling toxic gas in the resort of Tulum, but the source hadn’t been determined. Iowa officials identified the family as 41-year old Kevin Sharp, his 38-year old wife Amy, and their children, 12-year old Sterling, and seven-year old Adrianna, all of whom were from Creston. According to reports, their bodies are expected to be returned to the U-S on Wednesday.

If it was a gas leak the took the family’s lives, it wouldn’t be the first time faulty gas connections killed tourists in the area. In 2010, the explosion of an improperly installed gas line at a hotel in the nearby town of Playa del Carmen killed five Canadian tourists and two Mexicans. In that case, prosecutors said the heating-gas line, apparently meant to fuel a pool heating unit, was not properly installed or maintained. They claimed a leak from the line may have been set off by a spark from an electric switch or plug. A judge later dismissed criminal charges against five contractors and employees at the hotel.