Mr James Charles Kopp, the murder suspect whose extradition from France is sought by Washington, had been in Brittany for less than two weeks when he was arrested by police in Dinan on Thursday.
"He stayed in hotels, youth hostels. He moved every two or three nights," Commdt Noel Renard of the Dinan police force told The Irish Times.
Commdt Renard did not know whether Mr Kopp arrived in Brittany from Ireland, but said he carried two Irish passports as well as his US travel documents.
"We don't know if they're fake," Commdt Renard said. "They look real to us. Both have the same photo but different names. Ireland is involved in this affair, because he used Irish passports to hide."
Police in Dinan were alerted by the FBI that Mr Kopp was in the region and was expected to collect money at the post office. "We were tipped off by someone watching the distribution point," Commdt Renard said.
"We arrested him on the pavement 300 or 400 metres from the post office, in the centre of the old town. He had a password to retrieve funds arriving under his false identities. An anti-abortion group in the US devised a way to send money to him."
Mr Kopp refused to speak when the Dinan prosecutor, Ms Christine Le Crom, attempted to question him yesterday. He was transferred to prison elsewhere in Brittany.
Commdt Renard said he was ordered not to reveal the location, but it is believed to be Rennes, where the appeals court is awaiting evidence against Mr Kopp before deciding whether to extradite him.
France abolished the death penalty 20 years ago. The frequency of capital punishment in the US - and the execution of minors and mentally retarded people - are considered scandalous here and are vigorously denounced by intellectuals led by the former justice minister, Mr Robert Badinter.
"He cannot be extradited unless the French government receives assurances that the death penalty will not be requested, sentenced or enforced," a spokeswoman for the justice department said.
The state of New York, where Mr Kopp would be tried for the October 1998 murder of a gynaecologist who performed abortions legally, enforces the death penalty.
The French Prime Minister would have to sign an extradition order. Even then Mr Kopp could delay proceedings by taking his case to the Conseil d'Etat.
Mr Ira Einhorn, an American convicted in absentia of murdering his girlfriend in 1977, has avoided extradition from France to the US for nearly four years.
