MOUNT CLEMENS, Mich. —  An ex-teenage au pair says she had sex with Stephen Grant the night before he's accused of strangling his wife Tara, then dismembering her body and scattering the parts.

Now-20-year-old Verena Dierkes came from Germany to testify in Stephen Grant's first-degree murder trial in Macomb County Circuit Court.

She was living with the Washington Township couple and caring for their two children when 34-year-old Tara Grant died February 9.

Dierkes says Stephen Grant had flirted with her for months and says they slept together the night of February 8. Dierkes says the Grants' 6-year-old daughter entered the bedroom, and Dierkes hid under the covers.

The 37-year-old defendant pleaded guilty to mutilating a corpse.