BERLIN — The case would have stoked public outrage if the mother had known her young son was being raped and had done nothing to stop it.

But when Germans heard that she and her boyfriend had raped the boy themselves and served him up to pedophiles on the dark web, the fury only grew.

The mother and her companion — identified only as Berrin T., 48, and Christian L., 39, in keeping with German privacy laws — were convicted on Tuesday of sexually abusing her son over the course of two years, beginning when he was about 7. The abuse included inappropriate touching, rape and making videos that were placed as advertisements on the dark web for pedophiles — among them a German soldier — who paid the couple thousands of dollars to abuse the boy.

For many Germans, the most horrific part of a horrific case was the woman’s complicity, which violated deeply held assumptions about motherhood and contradicted the common image of sexual predators as male. But the case also shocked the country for the severity of the abuse and the failure of authorities to protect the child, despite repeated opportunities for intervention.