Presidio County Dist. Atty. Rod Ponton cited the letter Tuesday when he told the Associated Press there was nothing suspicious about the Feb. 13 death of the 79-year-old jurist.
He said the long list of health problems made an autopsy unnecessary.
Ponton had a copy of a letter from Rear Adm. Brian P. Monahan, the attending physician for members of Congress and the Supreme Court. The letter was to county Judge Cinderela Guevara, who conducted a death inquiry by phone and certified Scalia's death.
The letter dated Feb. 16 said Scalia's many "significant medical conditions led to his death," Ponton said.
In the letter, Monahan listed more than half a dozen ailments, including sleep apnea, degenerative joint disease, chronic obstructive pulmonary disease and high blood pressure. Scalia also was a smoker, the letter said.
Ponton declined to provide a copy of the letter, saying an open-records request must be submitted to Guevara, who did not respond to a phone message Tuesday.
Scalia was found dead in his bed at a Texas ranch, where he had gone on a hunting trip.
Guevara, who as county judge is the top administrator in the area, previously told the AP that she conferred by phone with Presidio County Sheriff Danny Dominguez and a U.S. marshal before certifying Scalia's death. On the day he died, she also conferred with Monahan by phone before determining the cause of death.
In rural Texas, justices of the peace investigate deaths, among other duties, but the two justices in the region were out of town and unavailable. Guevara was also out of town, more than 60 miles away, but agreed to conduct the death inquiry by phone.
The Supreme Court does not provide regular reports about the justices' health. It is left to each court member to decide how much to make public about medical conditions.
Some justices, including
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