CLOVER, S.C. (CBSNewYork) — A woman in South Carolina has been charged with killing her husband by putting eye drops in his water over several days.

Police say Lana Clayton, 52, confessed after an autopsy revealed a high level of Tetrahydrozoline in her husband’s body.

That’s the chemical found in over-the-counter eye drops, which can cause poisoning when it’s ingested.

Her 64-year-old husband, Stephen, was found dead at their upscale waterfront home on July 21st.

Investigators say the motive wasn’t immediately known.