It appears that US-15820 could refer to a case number, a document identifier, or another form of reference that involves both Bella Rossi and Izamar Gutierrez.
Without further context, it's challenging to provide specific details about their involvement or the nature of US-15820. However, I can suggest that such a designation might be used in legal, investigative, or administrative contexts. US-15820 Bella Rossi and Izamar Gutierrez