A contaminated salad containing duck meat is suspected of having killed five residents of a care home for the elderly in southern France.
Four women and a man, aged from 76 to 95, died after eating the salad on Sunday night. In all, 20 people at the home near Toulouse suffered vomiting and other symptoms of food poisoning.
Twelve of those taken ill are in hospital, but not in grave danger.
The salad ingredients, including duck foie gras (pâté), are being examined.
Prosecutors have put the suspicious ingredients under lock and key, as they prepare possible manslaughter charges against the management.
French media report that the privately-run home - La Chêneraie, in rural Lherm - passed a hygiene inspection in February.
A granddaughter of one victim told the local daily La Dépêche du Midi: "I've still got the menu in my bag and I know that last night they ate Périgord salad. So what does that mean? Maybe it was the foie gras?"
The cause of death is not yet official, as the results of post mortems are awaited.
One of the victims, 93-year-old Antoinette, had Alzheimer's.
The home has 82 residents and was opened in 2006. Korian group, which manages it, says meals are prepared in the home's kitchen - not delivered from outside.
But Alain Lepeyre, whose mother was among the five who died, said the meals had been brought in. He said a doctor at the home had told him that.
A woman called Chantal, whose parents are at the home but did not fall ill, said special meals were prepared for certain residents - and that was apparently the case in Sunday's fatal incident.
The tragedy in Lherm has fuelled a French debate about the state of retirement homes - there have been many complaints of understaffing and poor quality of care.
The government is reviewing provision for the elderly, including care home jobs, and aims to create 80,000 extra posts in care homes - that is, 25% more - by 2024.