Soon after his release, in 1965 Sánchez was arrested and convicted of murder for the armed robbery of a jewelry store in Madrid, in which a security guard was killed. At the age of 23, he was sentenced to death for the robbery and murder and also received "sentences totaling 1,000 years for other crimes". His death sentence was commuted to 30 years in a military prison. Maintaining his innocence, Sánchez fought his conviction. Known as "El Lute", during several escapes from prison, he was listed by the police as Spain's "most wanted" criminal. His reputation became legendary, and he was a symbol of resistance to the oppression of the poor under Franco.