Police discovered the bodies of the Swiss man’s 65-year-old father and his 66-year-old mother in their rental apartment in Zollikon on Sunday at around 1pm after being alerted by a neighbour, 20 Minuten newspaper reported.
Zurich cantonal police confirmed in a statement on Monday that the victims were a man and a woman but did not disclose their ages.
Police also confirmed the arrest of a 30-year-old Swiss man but did state his relationship with the victims.
The force said it was conducting an investigation in cooperation with the local prosecutor’s office.
The 20 Minuten newspaper reported that it was a woman neighbour who discovered the couple, referring to the male victim as an “asset manager”.
“The dead man had a knife in his back, and also the body of the woman was in the apartment,” the neighbour told the newspaper.
The neighbour said she entered the apartment after hearing a loud argument.
She told 20 Minuten that police arrested the couple’s son in connection with the deaths.
Police have not commented on this information and said they would be releasing further information “in the next few days”.