Investigators in Delaware County spent more than two hours digging in the Collingdale yard on Tuesday and a team of police dogs was also on the scene.
Chief Robert Adams said 30-year-old Melissa Rodriguez "is not anywhere on this property."
Police obtained a warrant after cadaver dogs alerted investigators to a backyard area earlier this month.
Police say Rodriguez told her husband April 19 that she was going to spend the weekend with friends in New Jersey, but the friends say she never arrived.
Adams says the case has been classified a missing person investigation, and no charges have been filed.