What vital information is revealed when John Berry meets Peter Randall for lunch?

When John agrees to meet Peter Randall for lunch, he makes new discoveries that are vital to Art Lee's case. First, Peter explains that he is not the real abortionist for whom they are looking. Next, he and Ev reveal that they are having an affair. They explain that Art had performed an abortion on Ev who had been carrying Peter's child. Ev says that after Karen's death, she was afraid that Peter would be implicated, so she falsely named Art as the abortionist.