Legal Definitions - Ker–Frisbie rule

The Ker–Frisbie rule is a legal principle that states a court's authority to try a criminal defendant is not affected by the way that person was brought into the court's jurisdiction, even if the method of their return was illegal or irregular. This means that if someone is unlawfully arrested, abducted, or improperly extradited from a foreign country or another jurisdiction, the illegality of their capture or transfer does not prevent a court from proceeding with their trial for the crimes they are accused of committing.

Here are a few examples to illustrate this principle:

• Example 1: International Abduction by Government Agents

  A notorious international hacker, wanted for cyberattacks against critical infrastructure in the United States, flees to a small island nation that has no extradition treaty with the U.S. U.S. law enforcement agents, without official permission from the island nation's government, covertly apprehend the hacker and transport them back to the U.S. to face charges.

  How it illustrates the rule: Despite the illegal abduction from foreign soil, the Ker–Frisbie rule dictates that a U.S. court can still proceed with the trial for the cybercrimes. The method of bringing the defendant into U.S. custody, even if unlawful under international or foreign law, does not prevent the U.S. court from exercising its jurisdiction over the criminal charges.

• Example 2: Irregular Interstate Transfer within the U.S.

  A suspect wanted for a serious felony in California is located and arrested in Nevada. Instead of following the formal interstate extradition process, which can be lengthy, Nevada police, at the urgent request of California authorities, simply drive the suspect across the state line and hand them over to California deputies without the required judicial hearings or paperwork.

  How it illustrates the rule: Even though the transfer between states bypassed the proper legal procedures for extradition, the Ker–Frisbie rule means that the California court's power to try the suspect for the felony is not affected. The irregularity in the arrest and transfer process does not invalidate the court's jurisdiction over the crime itself.

• Example 3: Abduction by Foreign Government at U.S. Request

  A former government official, accused of espionage, flees to a country with which the U.S. has a strained relationship and no extradition treaty. The U.S. secretly persuades a rogue element within that foreign government's security forces to abduct the official and deliver them to U.S. agents waiting at the border.

  How it illustrates the rule: Here, even if the foreign government's actions were illegal under its own laws or international norms, and instigated by the U.S. in an irregular manner, the Ker–Frisbie rule would still allow a U.S. court to try the official for espionage. The court's jurisdiction over the crime is maintained, regardless of the controversial and potentially illegal means used to bring the defendant into U.S. custody.