SAN ANTONIO -- A 34-year-old man was arrested in San Antonio and charged with sexual assault of a child.

Authorities said the girl's grandmother caught Stephen Sawyer in the act.

The grandmother kicked him out of the house and called the police. The 16-year-old victim told police what happened and Sawyer was later arrested.

According to the affidavit, Sawyer met the victim on Mocospace, a social network. The two then began talking on Facebook.