Police said the facts were still unclear but a man called Monday evening to report that a woman at a Zurich train station needed help. When police found her, she had the letters carved into her skin and told them she had suffered a miscarriage after the attack.
Brazil's O Globo newspaper reported that three skinheads, one with a Nazi symbol tattooed on his forehead, attacked the woman outside a local train station in Zurich while she was heading home. She had been speaking in Portuguese to her mother on a cell phone when she was accosted, it said.
The Brazilian Foreign Ministry gave similar details.
Pictures of the smiling, pregnant woman were splashed across Brazilian newspapers next to those of a bare stomach and legs with the initials SVP - presumably for "Schweizerische Volkspartei" (Swiss People's Party) - clearly visible in several places.
The woman has been identified by family members as 26-year-old Paula Oliveira, a lawyer working for European shipping giant A.P. Moller-Maersk A/S.
"What they did to my daughter is like a horror movie," the woman's father, lawyer Paulo Oliveira, told Brazil's Globo TV. He said she was cut about 100 times in an attack that lasted 10 minutes.
The woman moved to Switzerland several years ago to work for Maersk, and was pregnant with twins and planning to soon get married, according to her uncle Silvio Oliveira.
The Swiss People's Party has taken a hardline against immigrants. It has spearheaded campaigns against Swiss integration in Europe and pressed to toughen asylum laws and make it easier to expel foreign nationals.
But the party is part of Switzerland's broad coalition government and has never had links to neo-Nazism.
"This is a country of law, where every human being deserves respect," Oskar Freysinger, a hardline nationalist lawmaker in the party, told The Associated Press. "If that really was someone from our party, we wouldn't hesitate for a second. That person would be immediately kicked out."