The diplomat, who was raped outside the venue of the International Film Festival of India in the national capital, has returned to Switzerland, the country's Ambassador to India Walter B Gyger said on Thursday.
The 35-year-old Swiss woman was raped after being abducted in her car on Tuesday night by two men who abandoned her in the vehicle far away from her home in the posh Westend area of southwest Delhi.
The woman was leaving Siri Fort Auditorium after watching a movie at the IFFI at around 10 pm when she was assaulted.
The Swiss embassy on Thursday shot off a note reminding the External Affairs Ministry that under the Geneva Convention the security of diplomats was the responsibility of the host country.
"We are really shocked and saddened over the incident. We do not know how this can happen in a city like Delhi. We hope the criminals are arrested soon and punished.
"We are receiving all the support from the Indian authorities that we can expect. This is not the moment to complain. I have full confidence that the security forces in Delhi will take necessary measures," Gyger told PTI.
The government has termed the incident as "most unfortunate" and expressed keenness to see justice being done.