The Williamson County Sheriff's Office is following a new lead in the search for Rachel Cooke. The 19-year-old woman who was last seen jogging near her Georgetown home has been missing for three weeks.

Investigators are looking for a man they think may be a witness in the case. Deputies released a composite of the man.

They describe him as dark complected, about 19 or 20-years-old, with dark hair.

He was last seen wearing a cap and driving in the Northlake subdivision on Jan. 10. Deputies said the man was in a late model white sports car with either a black stripe or black molding.