Karlsruhe police spokesperson Ralf Minet said the teenager's mother is pressing charges of theft against her son, who admitted he pawned the jewellery to pay for the prostitutes.
"We don't know what the mother's motives are for pressing charges," Minet said. "It's possible she wants to teach him a lesson or it's possible that she felt she had lost control."
Police are also investigating the brothel that the boys said they visited. Prostitution in Germany is legal but the clients must be aged 18 or over. The operator of the brothel told police they had sent the boys away because they were under age.