The discredited expert witness whose testimony has jeopardized the conviction of a District woman for killing her 2-year-old goddaughter is under investigation for perjury in a Wisconsin case, prosecutors said.

The perjury investigation comes as the D.C. Court of Appeals is considering whether to grant a new trial to Angela O’Brien, who was sent to prison in 2001 for the high-profile case of Brianna Blackmond in part because of the testimony of the expert witness, Saami Shaibani, of Lynchburg, Va.