(CNN) A former US Army soldier who has been on death row since 1988 for raping and murdering several women could now face execution after a judge denied his bid for another stay of execution.

Judge J. Thomas Marten of the US District Court for the District of Kansas wrote last week that a previously granted stay of execution to Ronald Gray was "no longer in effect," denying his request to further block the military from carrying out the death sentence.

If Gray is put to death, it will be the first military execution since 1961, when John Bennett was hanged at Fort Leavenworth prison in Kansas after he was convicted of raping and attempting to kill an 11-year-old Austrian girl.

The current military method of execution is lethal injection.

Gray is one of six former servicemen currently on the military's death row at Fort Leavenworth. The most recent addition to that group is former Army Maj. Nidal Hasan, who was convicted of 13 counts of murder and 32 counts of attempted murder after his 2009 shooting rampage in Fort Hood, Texas.

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