Authorities in Germany say they have arrested eight suspected members of an online pedophile network in what they describe as one of the most serious child sexual abuse cases they ever investigated.

Police in the southwestern city of Freiburg say those arrested include a 47-year-old German woman suspected of letting others rape her own son in exchange for payment between 2015 and 2017.

The woman and her 37-year-old partner, who weren't identified, are also accused of abusing the child themselves.

In a statement Thursday, Freiburg police said others arrested were two Germans, including a soldier; a Swiss man; and a Spanish citizen. In a separate statement, Baden-Wuerttemberg state police said they also arrested two other men from northern Germany.

All arrests occurred last fall.