Colorado officials have issued an AMBER Alert for a teen missing from the Denver area. The alert was issued just before midnight last night for 17-year-old Samantha Herrera. Herrera was last seen in Sheridan yesterday afternoon and is thought to be traveling with 19-year-old Rodney Brown. Brown is considered violent and authorities say he may be armed. The pair may be traveling in a white Honda Accord with Colorado license plates. Anyone who sees the two teens or knows their location is asked to call 911 to report it.