Can Extradition Be Denied if Evidence Was Obtained Improperly Abroad?

Hi everyone. Suppose foreign investigators gathered evidence in a manner that would not comply with U.S. constitutional standards, such as through searches or seizures that might be considered unlawful domestically. If that evidence forms the core of an extradition request, can its origin be challenged in a U.S. court? I am trying to determine whether arguments about improper investigative methods are examined during the certification process.