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Muenster, Germany - Investigations into a man accused of poisoning the packed lunch of one of his colleagues are now focused on two possible poisoning cases, German police said on Tuesday.

A 56-year-old man has been in custody since Thursday after he was charged with the attempted murder of one of his colleagues.

The colleague informed the management after he noticed a suspicious powder in on his sandwich in early May.

Police said on Tuesday that the focus of their investigation was on two cases of illness and that they have not ruled out further cases. No indication was given of the symptoms.

According to unconfirmed reports in the German tabloid press, one of the employees has been in a coma with mercury poisoning. The local Westfalen-Blatt newspaper reported that the second victim was receiving dialysis.