VIENNA (AP) — Vienna police launched a criminal investigation after three women were found dead in a brothel, authorities said Saturday.

A witness discovered traces of blood outside the building, located near the Danube River, and alerted police on Friday afternoon. The bodies of the three victims had “cuts and stab wounds,” police spokesman Philipp Hasslinger told The Associated Press.

A 27-year-old man was arrested shortly after in the vicinity of the brothel carrying a knife, the alleged weapon. Police said the suspect will be questioned later Saturday.

Police found a fourth woman inside the brothel and police were questioning her as a witness.

The identities of the three victims are still unclear. Brothels are legal in Austria.

By Sam