A water heater that “was leaking gas, maybe from use or lack of maintenance" was likely the source of the toxic fumes that led to the deaths of an Iowa family last week in their Mexican vacation home, one of the country’s prosecutors revealed Monday.

The head prosecutor of the Caribbean coast state of Quintana Roo, 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, according to the Associated Press.

Iowa 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.

Autopsies had indicated the family died from inhaling toxic gas in the resort of Tulum, but the source hadn't been determined.

Jana Weland, Amy Sharp's cousin, told the Des Moines Register Monday that they were informed of the suspected source of the leak by the U.S. Consulate in Mexico. The family is working on getting the bodies back to U.S. soil for a funeral.

Photos released by Pech's office over the weekend 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 defense office of Tulum would issue a technical report on the findings.

The family was reported missing by relatives in their hometown about a week after the family left for vacation. Creston police contacted the U.S. State Department, and the bodies were found Friday during a welfare check at the condo in Tulum, on the Yucatan Peninsula.

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

The developer of the condo complex where the deaths occurred declined to comment Friday.

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.

The sister, Renee Hoyt, said the Sharps were scheduled to return to the U.S. last week. They were set to depart from the Cancun airport on Wednesday and fly to St. Louis on a non-stop flight.

When the family didn't arrive in St. Louis, family members contacted authorities, she said.

The father, Kevin, used to race stock cars at Adams County Speedway in Corning, notching eight wins over his career.

Bob Harris, the longtime public address announcer at the track, told the Des Moines Register that Sharp was nicknamed “The Sharpshooter” and hailed him as a “true family man.”

Sharp’s No. 2 cars would have themes of things that were important to him, such as breast cancer awareness, according to the newspaper.

"He was truly a champion on both sides of the fence at the speedway," Harris said.

Fox News' Dom Calicchio and The Associated Press contributed to this report.

