A crew member of a Royal Caribbean cruise ship was found dead in the Mexican resort island of Cozumel, possibly the victim of a violent crime, authorities and company officials said Sunday.Full story
Autopsies were being performed Sunday on the bodies of a young mother and three small children found slain in what was described by police as a violent crime scene in north Florida. Full story
Mental illnesses like schizophrenia or bipolar disorder alone do not make people more violent, but the tendency of people with psychiatric problems to abuse drugs or alcohol does, scientists said on Monday. Full story
Chicago police are searching for suspects in 15 different shootings that left 19 people dead late last week. NBC's Jeff Rossen reports.