Ann Madsen was a witness against her corrupt business partner, Steven Green, in the murder of their employee Harry Rankmeyer. She and Green ran a baby food company, Nature's Way, with Rankmeyer as their CFO. When Rankmeyer discovered that Green was cutting costs by allowing tainted baby food to go on the market, Green ordered him killed; Madsen saw Green with the assassin, Nikolai Rostov, the day of Rankmeyer's murder.
When Benjamin Stone questions her in front of a jury, she perjures herself and says that she had never met Rostov; she is terrified that Green, who has connections to the Russian Mafia, will have her killed as well. Stone threatens to charge her as an accomplice to the murder if she doesn't testify. Madsen reluctantly admits she lied and identifies Rostov, and is put in witness protection. Before she can be moved to a safe house, however, an unknown assassin shoots her dead in the street before he himself is shot to death by the police. Stone feels responsible for her death, and resigns from the DA's office.