Relevant developments include increased attention by the U.S. judicial system to the application of constitutional standards to evidence from foreign sources; the passage of statutes that provide U.S. courts with jurisdiction to try crimes that occur beyond U.S. boundaries; and treaties that clarify the ability of some police agencies to assist their foreign counterparts in investigations, searches, and seizures. U.S. courts have ruled that the fourth amendment is not implicated during searches and seizures by foreign officers who act independently with respect to U.S. citizens or foreign nationals. However, when U.S. authorities are invited to participate in searches and seizures abroad, the fourth amendment will apply to U.S. citizens, but not to foreign nationals. In addition, the courts are likely to refuse to admit statements that were involuntarily made, whether by a U.S. citizen or foreign national. A wide range of statutes now provide U.S. courts with jurisdiction over illegal activities that occur outside U.S. borders and territories. U.S. courts can try these cases, however, only when there is personal jurisdiction over the defendant, i.e., when the defendant is physically present in the courtroom. In the event the defendant must be brought from another country to be tried in the United States, the international law enforcement community must seek mutually acceptable means for securing the rendition of the defendant to the forum of prosecution. 42 footnotes