Rudy Hermann Guede, 20, was arrested Tuesday in the western German city of Mainz, an investigator in Perugia told The Associated Press on condition of anonymity because he is not authorized to speak to the media.
Guede had emerged Monday as another suspect in the slaying of 21-year-old Meredith Kercher, found stabbed to death Nov. 2 in her Perugia apartment. Three others, including Kercher's American roommate, Amanda Marie Knox, and her Italian boyfriend, Raffaele Sollecito, have been jailed in Perugia.
However, a judge on Tuesday authorized the release of one of the men detained after Kercher's death, bar owner Diya "Patrick" Lumumba, due to lack of evidence, the ANSA news agency reported.
Defense lawyers and court officials were not immediately available to confirm.
The three suspects jailed in Italy have denied wrongdoing. However, authorities said they found Knox's DNA on the blade of a knife implicated in the killing that belongs to her boyfriend, and a bloody fingerprint on a bedsheet led investigators to Guede, an Ivorian former basketball player who has been living in Italy since childhood, Italian media reported.
Italian police traced Guede to Germany through a friend who established Internet contact with the suspect Monday night and chatted with him for hours, the investigator said.
Police in Mainz confirmed they had arrested a 20-year-old native of the Ivory Coast, who appears to be the suspect. The man was arrested on a train bound for nearby Frankfurt for traveling without a ticket, said Mainz police spokesman Achim Hansen.
The man is to be brought on Wednesday before a German judge, who will rule whether he can be kept in custody on the Italian warrant, said Karl-Rudolf Winkler, a spokesman for prosecutors in Koblenz who have now taken over the case.
If he is ordered held, Koblenz prosecutors will then begin preparing a case for his deportation, he said.
In Perugia, Police Chief Arturo De Felice praised international cooperation and said Guede will be transferred to Italy as soon as possible.
"It's a matter of days, only days," he told the Italian news channel SkyTG24. "There was a trail to Germany; we knew that it could be one of the places where he could have sought refuge."
Lumumba's lawyer said his client was expected to be released imminently after the judge's ruling. "Lumumba is serene; he knows he will come out of this, there is no trace, nothing that leads to him," Giuseppe Sereni said.
According to court documents, Lumumba became a suspect based on Knox's accusations. However, the American was confused about the events because she had smoked hashish the night of the killing, a judge said in a ruling ordering the three held in custody.
No physical evidence has emerged tying Lumumba to the crime scene, and witnesses have placed him at his bar the night of the murder.