Police spokesman Carl Baker says officers arrived at the family's home about 5:30 a.m. Saturday to find the 46-year-old woman dead and her 21-year-old sister injured.
They found the woman's 25-year-old son, Pablo Hernandez Jr., outside the home.
Baker says Hernandez was arrested for investigation of murder and attempted murder.
Authorities didn't reveal the extent of the younger woman's injuries, but say she is hospitalized after undergoing surgery.
They asked that anyone with information on the incident contact them.