Mexican citizen Javier Suarez Medina is set to die by lethal injection later tonight for the 1988 murder of a Dallas narcotics officer in a case that has strained US-Mexico relations.
Barring an 11th-hour reprieve in the courts or from Texas Governor Mr Rick Perry, Suarez, 33, is to be executed in the Walls prison unit in Huntsville shortly after midnight Irish time.
He was condemned for shooting and killing undercover police officer Lawrence Cadena, 43, during a buy-and-bust drug sting in a Dallas parking lot on December 13th, 1988.
The Mexican government has intervened in the case saying Suarez' rights were violated because he was not put in contact with the Mexican consulate in Dallas at the time of his arrest, as required under the Vienna Convention diplomatic treaty.
Mexico has filed an appeal to the US Supreme Court making that argument and also charging Suarez suffered cruel and unusual punishment because he has been scheduled 14 times for execution, only to be saved in the end by legal maneuvers.
Twelve Latin American nations and two in Europe - Spain and Poland - have filed a legal brief in support of the Mexican appeal, she said.
The UN High Commissioner for Human Rights Mary Robinson has also joined the effort, urging in a letter to US Secretary of State Colin Powell that the matter be reviewed.
Mexican President Vicente Fox also has been involved, writing and talking by phone to Perry in an attempt to stop the execution.