Police have opened a homicide investigation after Rachelle Bergeron was shot dead on Monday night.
Police suspect a single shooter was behind the the US citizen's death.
The national government has confirmed the US citizen's death.
"The State of Yap, with the assistance of the FSM Department of Justice and the U.S. Federal Bureau of Investigation, are coordinating efforts to complete a thorough investigation," it said in a statement.
"We will disseminate information as it becomes publicly available."