A South Carolina woman admits she killed four members of her family but says she was mentally ill at the time she gunned down her two sons, her ex-husband and her stepmother.

Susan Hendricks pleaded guilty Friday to four counts of murder in the shooting deaths in October 2011.

Authorities say the 49-year-old Hendricks tried to make it look like one of her sons killed the others before he committed suicide. Investigators say she was trying to collect about $700,000 worth of life insurance policies.

The killings took place in two homes in Liberty in the northwest part of the state. Authorities say Hendricks also killed a man in 2006, but claimed self-defense. Charges were never filed in that case.

Hendricks will be sentenced after a hearing Friday.