But further details were not disclosed.
The alleged assailant, 36-year-old Phat Nguyen of Lancaster, also was injured. He faces aggravated assault and weapons charges.
Shellem said Nguyen and the woman had recently broken up, and he was hiding between vehicles when the victims arrived at the woman's home around 12:40 a.m.
Nguyen then attacked the pair, who tried to fight him off, and he was soon subdued by a neighbor who heard the commotion.
It was not immediately known if Nguyen had retained a lawyer.