Winter, 1910 Panzram alleged in his 1929 autobiography that after serving a short sentence at Rusk Texas, he claimed to have gone to Juarez, Mexico to try to enlist in the Federal Mexican Army; he then left on a train for Del Rio, Texas and got off in a small town 50 to 100 miles east of El Paso, Texas where about a mile south of that town he alleged to have abducted, assaulted, kicked and strangled a man and then stole $35.00 from the victim
In light of his extensive criminal record, he received a 25-years-to-life sentence. Upon arriving at Leavenworth Federal Penitentiary, he warned the warden, "I'll kill the first man that bothers me", and was given a solitary job in the prison laundry room. On June 20, 1929, he beat the Prison laundry foreman Robert Warnke to death with an iron bar, and was sentenced to death.He refused to allow any appeals of his sentence. In response to offers from death penalty opponents and human rights activists to intervene, he wrote, "The only thanks you and your kind will ever get from me for your efforts on my behalf is that I wish you all had one neck and that I had my hands on it."