Clark County Sheriff's deputies say the mother of a 7-week-old boy who died last year has been arrested on an involuntary manslaughter charge. Prosecutors believe 19-year-old Shania Delawder beat and killed Liam Spencer, whose body was found at a motel last October. Delawder told investigators last week she knew her son was severely injured, but didn't seek medical attention. Charges against Delawder and the boy's father were dropped last year.