A migrant is accused of stabbing his roommate to death and then killing a coworker - both within hours on the same night. Rony Yahir Alvarenga Rivera, 22, was charged with one count of first-degree murder and two counts of second-degree murder in Nassau County, New York , according to ABC 7 . Officials say the suspect is from El Salvador and has been in the U.S. illegally since he was 12 years old. A 32-year-old woman was found dead at the Valley Stream, New York, home that she shared with Rivera, according to police. Her name has not been released. Investigators say that the killing happened around 9 p.m. Thursday. Around midnight, authorities responded to a nearby Wendy’s for a report of a person with a knife, according to ABC 7. When police arrived, they found a 42-year-old mother of two dead at the fast-food restaurant. That victim’s name has not been released but she was a coworker of Rivera at the Wendy’s. Rony Yahir Alvarenga Rivera is accused of stabbing two women to death in New York.…