A disgruntled postal worker accused of fatally shooting his supervisor at an Ohio post office and later killing a postmaster has been indicted on federal charges carrying the possibility of a death sentence.

The indictment announced Thursday by county and federal prosecutors charges 24-year-old DeShaune Stewart, of Columbus, with two counts of murdering an officer of the United States.

Authorities say Stewart shot and killed 52-year-old Lance Dempsey at a post office in suburban Dublin in December. They say he then killed 53-year-old Ginger Ballard at an apartment complex.

Authorities say Stewart was naked during both attacks.

Police say the violence appeared to be retaliation for Stewart's pending dismissal at work.

A message seeking comment was left with Stewart's public defender.