Paris, France (CNN) -- A woman has been charged over the discovery of the bodies of eight newborn babies at two locations in northern France, the French Interior Ministry said Thursday.

Gendarmes found the remains in the village of Villers-au-Tertre, south of Lille, some in a home and others in the garden of another home.

The woman has admitted giving birth to and killing the babies and has been charged with voluntary manslaughter, prosecutor Eric Vaillant said. But her husband has not been charged after telling investigators he knew nothing of the pregnancies and deaths, he said.

The couple are in their mid-forties. The woman is a nursing assistant while her husband is a member of the local council, a neighbor told AFP.

"These are attractive, helpful, polite and courteous people, who did nothing to make you think them capable of anything abnormal," he said.

Another resident said the couple had two grown-up daughters and were grandparents, AFP said. The pair had lived in the village for at least 15 years, neighbors said.

Former mayor Daniel Collignon said Villers-au-Tertre was a quiet, rural community. "I'm still in shock," he told AFP.

Police said a man digging in his backyard found the remains of two newborn children and called police. The man said he bought the home from another couple who live a few minutes' drive away.

When police searched the couple's home with sniffer dogs they found the bodies of six infants, they said.

Psychotherapist Lucy Beresford told CNN that very little was known about the circumstances of infanticide because it was a taboo subject.

Research suggested that women who denied or concealed their pregnancies, for whatever reason, were a "high-risk" group, she said. But other factors could trigger infanticide as well.

"It could actually be to do with the social isolation of the mother, or it could be their psychopathology prior to pregnancy," Beresford told CNN.

"For example, do they have a history of substance abuse or other mental health concerns that have contributed to them being in this situation which they cannot accept as a reality?"

Postnatal depression could also be a possible contributory factor, she said.

"That could be because when they're depressed they're not really of sound mind. It could be that they genuinely believe they are unworthy to be a parent. Or it could just be the level of disordered thinking that comes with being depressed."

CNN's Phil Black contributed to this report.