The Lacey man is accused of stabbing his 59-year-old mother to death Monday in the garage of her home. Frankie Johnson was killed with a screwdriver.
Lewis also is accused of using a screwdriver to fatally stab a former neighbor, 67-year-old Charles "Wes" Simpson at his home. He died Thursday in a hospital.
The Olympian reports Thurston County Deputy Prosecutor Andrew Toynbee filed the murder charges Thursday.
Lewis is held on $2 million bail in the Thurston County Jail, waiting for a mental evaluation. He's also charged with robbery in the theft of his mother's ring and animal cruelty in the death of his mother's dog.