GATESVILLE, Texas -- The Gatesville Police Department on Sunday reported that while the cause of a deadly explosion at Coryell Memorial Hospital remains undetermined, the initial investigation shows a construction-related accident resulted in a natural gas explosion.

The department stated rumors that the explosion was the result of a buildup of large amounts of migrate gas in the gas lines are untrue.

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The department further stated it could take up to six months for the investigation to be complete.

As of Sunday morning, police reported, two blast victims remain at Parkland Hospital in Dallas, three remain at San Antonio Military Medical Center, and four are still being treated at Dell Seaton Medical Center in Austin.

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The explosion in Gatesville, which is located about 45 minutes from Waco, on Tuesday, June 24, claimed two lives and injured 14 other people.

Killed in the blast were 44-year-old Michael Bruggman, of Rogers, Texas, and 36-year-old Filiberto Morales, of Round Rock, Texas.