The man accused of stabbing two babies and a caregiver to death at a Belgian day care center has also been charged in the stabbing death of an elderly woman.

Lawyer Jaak Haentjes said his client, Kim de Gelder, was charged Thursday with killing a 73-year-old woman at her home near Antwerp one week before his Jan. 23 attack on the Dendermonde day care center.

In that attack, a 6-month-old boy, a 9-month-old girl and a 54-year-old caregiver were stabbed to death and ten other babies and two adults were slashed.

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De Gelder, 20, faces murder charges for those killings.

Haentjes has described his client as a mentally sick man who hears voices in his head. The suspect has been uncooperative under questioning about the day care center rampage.