Two Swiss women, aged 19 and 21, arrived at the car park of the Wil train station on Monday night to settle a score with two 18-year-old women, one Turkish, the other Bosnian, daily newspaper Blick reported online on Wednesday.
The Bosnian woman lost a tooth and several other teeth were damaged, while she received a gash on the chin after one of the Swiss women allegedly beat her with the baseball bat, according to the report.
The Turkish woman suffered bruises while using pepper spray on the Swiss women, Blick said.
The Swiss woman wielding the baseball bat told the wesbite she was defending herself after first being pepper sprayed, while those beaten maintained the reverse happened.
Less than a year ago the antagonists were friends, with one of the rivals telling Blick that she celebrated New Year's Eve with one of the Swiss women.
But the situation deteriorated when insults were exchanged on Facebook followed by SMS messages on Whatsapp, which led to an agreement to meet at the train station.
All four women were locked up by police for two days.
The local prosecutor said a criminal investigation into the affair is under way, Blick reported.