Non-homicide crimes which may result in a federal death sentence:

Espionage (18 U.S.C. 794)

Treason. (18 U.S.C. 2381)

Trafficking in large quantities of drugs (18 U.S.C. 3591(b))

Attempting, authorizing or advising the killing of any officer, juror,or witness in cases involving a Continuing Criminal Enterprise, regardless of whether such killing actually occurs. (18 U.S.C. 3591(b)(2))

Sources: Bureau of Justice Statistics, Capital Punishment 2003 report.; Federal Death Penalty Resource Counsel Project


 http://www.deathpenaltyinfo.org/arti...cid=29&did=192
(at the bottom there, emphasis here added by Sinse)

In fact, it wouldn't surprise me if they tried to use this one that can be found on the Homicide related Crimes list -

Mailing of injurious articles with intent to kill or resulting in death. (18 U.S.C. 1716)