This article contains plot spoilers for the 2017 series of Twin Peaks.
Doris Truman was the wife of Sheriff Frank Truman.
She eventually moved with her husband to his hometown of Twin Peaks, where he took over as sheriff in his brother's stead. At some point, she and Frank had a son who was a soldier and eventually committed suicide.
She later returned to Frank, frustrated that her father's car seemed to have still not been repaired.