"they noticed Fritz Hammer – one of their older counterparts."

Hammer and Sickle
Public DomainHammer and Sickle
Fritz Hammer leads Liesel and Rudy to the stealing gang leader, Arthur Berg, who is himself a metaphor for Communism – redistributing the wealth among the poor. The symbol for the Soviet Communists was a sickle and a hammer, so Fritz Hammer is a fitting name.