Todd Walker is a friend of Nia Brooks.
His friend, Nia, was being sent death threats after getting into the Army Rangers. When her house was destroyed, he helped her clean up, but Alice and Danny noticed him taking the bags of trash with him in his car instead of putting them in her trash bins. They then had Nia tell him about going to AVI for help in order to get him to out who he was working with, the source of the death threats. Through this, they discovered that Nia's own brother Brian Brooks, was behind them. He claimed he was only trying to protect Nia.
He's a captain in the US Army.