Peterson , 31 , is charged with two counts of first-degree murder in the slayings of his wife , Laci , and their unborn son , Conner .
Peterson , 31 , is now charged with murder in the deaths of his 27-year-old wife and their unborn son .
A Cuban architect was sentenced to 20 years in prison Friday for using two fake grenades to hijack a passenger plane from Cuba to Florida in April .