He was charged with killing Robyn and Leamond Turnage during a robbery in their Hawthorne home.
Prosecutors also charged him on Wednesday with the September killing of 80-year-old Hanna Marcos in Hawthorne.
He was also charged in the murder of Denice Roberts, who lived on the same block as Ewell.
Ewell, who is being held without bail, is set to be arraigned November 30th.