Prosecutors gave formal notice Friday that they are seeking the death penalty for the two men accused in the federal building bombing that killed 169 people.

Timothy McVeigh and Terry Nichols “committed the offenses after substantial planning and premeditation to cause the death of one or more persons and to commit an act of terrorism,” U.S. Attorney Patrick Ryan argued in separate but nearly identical notices filed in federal court.

Ryan cited 13 aggravating circumstances that justify seeking the death penalty, including the fact that “various victims were particularly vulnerable due to old age, youth and infirmity.”

McVeigh and Nichols face a May 17 trial on murder and conspiracy charges. U.S. District Judge Wayne Alley has ordered the trial held in Lawton, about 90 miles southwest of Oklahoma City.