Rudd was last seen with her suspected abductor, Kahlil Tatum, March 1 in northeast Washington D.C.
Police found Kahlil Tatum's body Monday, saying he died of an apparent self-inflicted gunshot wound to the head.
Police released a short video of another man getting off an escalator and are hoping to learn his identity. They said they want to question him about Relisha's disappearance.
“The Metropolitan Police Department believes this individual may have information and we are only seeking to speak with him,” the agency said in a statement.
Police found Kahlil Tatum's wife, Denise Tatum, dead in a hotel room the day after the search for Relisha began.
Police said they haven't ruled out the possibility Kahlil Tatum killed Relisha.