Federal Bureau of Investigation, File, Associated Press
This file photo provided April 19, 2013 by the Federal Bureau of Investigation shows Boston Marathon bombing suspect Dzhokhar Tsarnaev. During a hearing Wednesday, June 18, 2014 a federal judge in Boston warned current and ex-members of prosecution team in the case from speaking publicly. Tsarnaev's trial is scheduled to begin in November.

BOSTON — A federal judge has ruled that "betrayal of the United States" should not be a factor in considering if Boston Marathon bombing suspect Dzhokhar Tsarnaev gets the death penalty.

U.S. District Court Judge George O'Toole said Wednesday it was "highly inappropriate" for prosecutors to draw a distinction between a "naturalized" and "natural-born" U.S. citizen.

Federal prosecutors argue Tsarnaev deserves death, in part, because he betrayed his allegiance to the U.S. after it gave him and his Russian-born family asylum and citizenship more than a decade ago.

Tsarnaev's attorneys argued that the federal government has never cited a defendant's immigration history in nearly 500 previous death penalty cases.

O'Toole also issued a stern warning to prosecutors about current or former members of its team speaking to the media.