County and federal prosecutors in Columbus said Friday that sending the case to federal court was a joint decision.
Police say 24-year-old DeShaune Stewart, of Columbus, shot and killed 52-year-old Lance Dempsey at a post office in suburban Dublin on Dec. 23.
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 against two people involved in Stewart's pending dismissal at work.
A message seeking comment was left at his public defender's office on Saturday.
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