Wally (Daniel London) was the precog's caretaker at the Precrime Temple. Yep, London is the one cast member reprising his role from the original Spielberg movie. On the series, he's thrilled to be reunited with Dash and will assist the crime fighting duo in any way he can.
Dash: You know how much I see out here. If I can just get to one in time. Agatha: You can't. You know that. Your gift is incomplete without your brother.