A judge in the southern U.S. state of Texas has set the execution date for a Mexican citizen who confessed to killing 12 people in the United States.

Angel Maturino Resendiz, known as the "Railroad Killer," is scheduled to be executed on May 10 for the murder of a Texan doctor in 1998.

Maturino Resendiz's attorney had asked for a delay in the scheduling, saying an appeal is pending. The attorney was hired by the Mexican government.

An appeal in 2004 was denied by the Texas Court of Criminal Appeals.

Maturino Resendiz has confessed to 12 murders in five U.S. states. The convicted killer traveled by stowing away on railroad cars, leading him to be dubbed the "Railroad Killer."

Some information for this report was provided by AP.