A woman and her baby daughter were found dead in a park in Rome. An American suspect was just arrested in Greece.

Greek authorities detained an American man Friday on the Greek island of Skiathos suspected of killing an infant found over the weekend in a Rome park and of having a role in the death of the infant’s mother, whose body was found nearby.

The American, who was not identified, was detained on a European arrest warrant issued in Italy, and he will be formally arrested when the warrant is forwarded, Greek police told The Associated Press. The suspect will appear before a judge in an extradition hearing next week and has the right to challenge his transfer.

The bodies of the baby girl and mother, also identified as Americans, were found in Rome’s Villa Pamphili park on Saturday, the Italian daily Corriere della Sera reported. The mother’s body was under a black bag, having been killed several days before the infant, who was found several hundred yards away in the undergrowth.

Police in Rome have refused to comment on the case, and a news conference was scheduled for later Friday.

Police theorize that the man killed the infant after returning to the park where the mother’s body had been left, the paper said.

Their relationship with the suspect was not immediately clear but police said they had been traced to a shelter for the needy near the Vatican, where they appeared to be a nuclear family.

Authorities were able to track down the suspect thanks to fingerprints on the bag covering the woman and a scrap of a tent, like ones provided to people without shelter, the newspaper said. He was located in Greece with mobile phone data.

According to the newspaper, the woman, who was around 30 years old, had a tattoo of a skeleton on a surfboard.

Corriere della Sera also reported that a little girl’s pink dress was found in a trash can near where the bodies were found.

The newspaper said forensic teams collected a total of 40 items, including a bra and a sleeping bag. Pictures from the scene showed officers scouring undergrowth and a wooded area in search of evidence.