William Sorukas, chief of the US Marshals Service's domestic investigations branch, told the Associated Press that investigators learned about the trip days in advance and were therefore able to prepare for an arrest.

BBC: Roman Polanski in Swiss detention

"The modern world of technology, because there is more information out there, it's that much more important for our people to be vigilant and for us to be vigilant, " said Harlow of the U.S. Marshals Service.

CNN: Inside the witness protection program