Does anyone know if it is standard for the FBI to get involved in American-on-American violence overseas? that caused the hotel staff to call the police before HM and TS took off.
Yes, it is, there are FBI legate or attaches that are agents in residence all over the world. You can find a list on the FBI website. Here is description of their role:
Their core mission is to establish and maintain liaison with principal law enforcement and security
services in designated foreign countries. This liaison enables the FBI to effectively and expeditiously conduct its responsibilities in combating international terrorism, organized crime, cyber crime, and general criminal matters. In particular, legat liaison activities are essential to the successful fulfillment
overseas of the FBI’s lead federal law enforcement mission to prevent terrorist attacks against citizens and interests of the United States. Liaison is carried out in accordance with executive orders, statutes,
treaties, Attorney General Guidelines, FBI policies, and interagency agreements. The legal attaché
program provides for a prompt and continuous exchange of information with foreign law enforcement and security agencies and coordination with U.S. federal law enforcement agencies that have jurisdiction over
the matters under investigation. Our foreign-based personnel also assist foreign agencies with requests for investigative assistance in the U.S. to encourage reciprocal assistance in counterterrorism, criminal,
and other investigative matters.
From what I read TS requested a voucher to use the internet using his own name and the staff recognized it as one of the names being broadcast on the BOLO and they then called the police.