But they have been unable to question the accused, in her 40s, because she was committed to a psychiatric hospital, according to a report on Monday.
“She has been indicted on the basis of the information from the inquiry,” Mulhouse prosecutor Hervé Robin told Swiss news agency ATS.
Michèle Zaugg-Röthlisberger, widow of Zaugg, was found dead in an outbuilding near her home on January 21st with wounds to the head.
The only daughter of the Zaugg couple was actively sought by police who discovered her three days later in the family property in Pfastatt, a suburb of Mulhouse.
The woman was subsequently admitted to a psychiatric hospital.
Prosecutor Robin acknowledged that given her “mental state” for the moment she cannot be questioned and “we don’t know when this will be possible”.
She was indicted as a “legal precaution” to guarantee her availability to the court, he told ATS.
The daughter had reportedly been in conflict with her mother following the death of the artist in 2005.
France 3 television said the conflict was over the artist's legacy.
Last October, the younger woman was released from a stint in a psychiatric hospital.
Zaugg was renowned as a “visionary” figure in the contemporary art scene.
Painter, sculptor and critic, he directed a retrospective art show dedicated to fellow Swiss artist Alberto Giacometti in Paris in 1991.
He also collaborated with well-known architects, including Basel-based firm Herzog and de Meuron, which designed his atelier in Pfastatt.