[1] In May 1934, Winstead and several other Western agents, including former Oklahoma City policemen Jerry Campbell and Clarence Hurt, were assigned to the Chicago Field Office to help apprehend John Dillinger and his gang of bank robbers.
Winstead is widely believed to have been the agent who fired the fatal shot into Dillinger during the FBI's ambush at the Biograph Theater, shooting him in the back of the head at close range.
While in El Paso he took under his wing a rookie special agent named William C. Sullivan, mentoring him and helping to launch a career that would ultimately make him one of the top figures at FBI headquarters in Washington, DC.
"[6] Although his formal education was minimal, the college-educated Sullivan remembered Winstead as "so well read that he stood out in sharp contrast to most men with college and graduate degrees, those who stopped learning when they left school.
Winstead instead refused this forced relocation, telling Hoover to "go to hell"[8] and resigning on December 10, 1942 — four years short of having accrued sufficient tenure for government retirement.
"I knew better than anybody that after doing my little bit from 1917 to 1920 to save the world for Democracy, and so many of the boys doing it again now, that I wasn't going so far as Oklahoma City as a penalty for exercising my rights of free speech," Winstead declared.
[11] Winstead returned to law enforcement after the war, serving various part-time jobs as a sheriff's deputy in New Mexico and a private investigator, before retiring and taking up horse ranching.