In correspondence from Iraq (web|news) 's fortified Green Zone, Col. Stephen Scott had always insisted to relatives that he was safe. But recently, family members noticed a surge in violence had him worried. "You could tell in his voice that he was telling us he was safe, but he wasn't really believing it in the last three weeks," his sister, Kathleen King said. Scott, who had ties to St. Louis, died Sunday during a mortar attack on facilities inside the protected Green Zone in Baghdad, which houses the U.S. Embassy. Only the ninth soldier of his rank to have been killed in the Iraq war, he is one of the conflict's highest-ranking casualties.

An avid jogger, 54-year-old Scott was killed as he exercised on a treadmill in a U.S. military facility, King said.

The war so far has claimed the lives of more than 4,000 U.S. soldiers. Two colonels were among 12 people killed in 2007 when a Black Hawk helicopter crashed near Baghdad.

Colonel appears to be the highest rank of any U.S. military deaths in the Iraq war. According to an Associated Press database of U.S. military deaths in Iraq, at least eight other Army or Army Reserve colonels have died in the now-5-year-old war.

The AP database includes casualties awarded the rank of colonel posthumously.

Scott had spent two years working at the Pentagon, but went to Iraq in December to help train and equip the Iraqi army. He had already served 18 months in Iraq, and his recent deployment was a short assignment that was set to end in June, King said.

Scott joined the Army immediately after graduating from Riverview Gardens High School in St. Louis County, King said. He wanted to follow in the footsteps of his father, Kenneth Scott, who also served in the Army.

"Really, I think it was all my father," King said. "He had dedicated his life to the Army and protecting our country, and that's all Stephen really wanted to do."

After leaving St. Louis, Scott spent more than 10 years based in Alabama, and still owns a house in the town of New Market, Ala., which the Army lists as his current address. He was assigned to the 356th Quartermaster Battalion based in Laurel, Miss.

Scott told reporters in February that he was pleased with the pace of development for the Iraqi army, according to American Forces Press Service.

"We are introducing more military sales to the (Iraqi) minister of defense, and we are making progress," Scott said, according to the article. "It is very important to their government and ours that they become capable of defending themselves very soon."

He said Iraqis referred to U.S. soldiers and officials as their brothers, according to the article.

But in recent weeks, as soldiers' barracks were targeted by mortar attacks, many soldiers took to sleeping in their offices, his sister said.

Also killed in the attack that claimed Scott's life was 36-year-old Maj. Stuart Wolfer of Coral Springs, Fla. He was assigned to the 11th Battalion, 104th Division, Boise, Idaho.

Scott's funeral will be at the First Baptist Church of Harvester in St. Charles County, King said. A date has not yet been set.