Since 1642 (in the 13 colonies, the United States under the Articles of Confederation, and the current United States) an estimated 364 juvenile offenders have been put to death by the states and the federal government. The earliest known execution of a prisoner for crimes committed as a juvenile was Thomas Graunger in 1642. Twenty-two of the executions occurred after 1976, in seven states. Due to the slow process of appeals, it was highly unusual for a condemned person to be under 18 at the time of execution. The youngest person to be executed in the 20th century was George Stinney, who was electrocuted in South Carolina at the age of 14 on June 16, 1944. The last execution of a juvenile may have been Leonard Shockley, who died in the Maryland gas chamber on April 10, 1959, at the age of 17. No one has been under age 19 at time of execution since at least 1964. Since the reinstatement of the death penalty in 1976, 22 people have been executed for crimes committed under the age of 18. Twenty-one were 17 at the time of the crime. The last person to be executed for a crime committed as a juvenile was Scott Hain on April 3, 2003 in Oklahoma.
 What method was used to free Leonard Shockley?