Samples for DNA analysis were taken on Thursday from the bodies of three women found with their throats cut in the Evros region near Greece’s land border with Turkey on Wednesday.
According to a coroner, the women were of Asian origin and might have been related.
The body of the oldest woman, aged between 20 and 30, bore multiple stab wounds, while the other two were aged 15-20 and 18-25, police said.
Two had had their hands bound. Investigators have yet to determine the motive behind the killings but suspect their smugglers might have wanted to demonstrate to other migrants what would happen if they failed to pay their crossing fees.