On Tuesday, a former nursing assistant at the Department of Veterans Affairs hospital in Clarksburg pleaded guilty to murdering seven men there. There may have been even more victims.

Reta Mays, 46, of Harrison County, West Virginia, entered her plea in federal court at Clarksburg. She is to be sentenced at a later date.

Federal authorities who investigated the deaths and worked out the plea agreement did not ask Mays why she killed the men. At some point in their pre-sentencing investigation, they should. If they cannot get an answer, perhaps U.S. District Judge Thomas Kleeh, who is likely to pass sentence on Mays, can.

Knowing why she killed men who had served our country is important — and could prevent future serial killings.