The adult female wolf, discovered in a field in the commune of Jaun last Friday, was taken to the University of Bern where an autopsy showed it had in all likelihood been poisoned, Fribourg's public prosecutor said in a statement.
Last week six foxes, a cat, a kite and a badger were also found dead in the same area.
Criminal proceedings have been opened against an individual for contravening animal protection laws, said the prosecutor, who gave no further details of the suspect.
The accused denies the charges.
People owning animals in the area are warned to keep them away from any abandoned food waste.
Wolves have gradually returned naturally to Switzerland in recent years after being eradicated by the beginning of the 20th century.
They are a protected species under Swiss law.