WASHINGTON (TNND) — The cause of death is becoming clearer in the sudden death of Senator Lindsey Graham, which was reported on Sunday morning. The Office of the Medical Examiner of the District of Columbia released its preliminary findings on what caused Graham's death.

The medical examiner report says preliminary findings showed Aortic Dissection due to Arteriosclerotic Cardiovascular Disease.

Graham died after what his office reported as "a brief and sudden illness" at the age of 71.

The medical examiner shared that a death certificate is pending until all testing is back.

“The death certificate will be PENDING until all the toxicological and microscopic testing are finalized and at that point the death certificate will be updated to reflect the cause of death and appropriately classify the manner of death," the medical examiner said.