KAUFMAN, Tex. — After the daylight assassination of his deputy two months ago, Mike McLelland, the district attorney in largely rural Kaufman County, responded with a flash of angry bravado, denigrating the perpetrators as “scum” and vowing to hunt them down.

A former Army officer who served in Iraq during Operation Desert Storm, Mr. McLelland carried a gun and refused to be intimidated, according to a friend and the local news media, even as his wife expressed unease, worrying that her husband, too, could be in danger.

“I hope that the people that did this are watching, because we’re very confident that we’re going to find you,” he said at a news conference hours after his deputy was killed. “We’re going to pull you out of whatever hole you’re in. We’re going to bring you back and let the people of Kaufman County prosecute you to the fullest extent of the law.”

On Saturday evening, the authorities found Mr. McLelland, 63, and his wife, Cynthia, 65, shot to death inside their home in Forney, Tex., in Kaufman County. The killings galvanized law enforcement officials and frightened and bewildered local residents, many of them still shaken by the shooting of the deputy, Mark E. Hasse, 57, on Jan. 31. That case remains unsolved.